Here's the thing, these two barely compete with each other. The Oura Ring 4 is a dedicated health tracker disguised as jewelry at $349 plus $5.99/month membership. The Apple Watch Series 11 starts at $399 and tries to be your phone, wallet, fitness coach, and medical device simultaneously. Some people wear both. Not crazy, actually the setup I'd recommend if budget allows. But most folks want one device, and picking wrong means overpaying for features you'll ignore.

Oura Ring 4 vs Apple Watch Series 11: Design and Daily Wear

The Oura Ring 4 is titanium inside and out, weighs practically nothing, and comes in six finishes from Silver to Rose Gold. Sizes 4 through 15. You forget it's there. Not marketing fluff, I genuinely forget mine until I bump it on a dumbbell. For sleep, it's perfection. No bulky screen pressing into your face when you roll onto your side at 3 AM.

The Apple Watch Series 11 weighs 34.6g (42mm), sits 9.7mm thick, and looks great with new ceramic coated ION X glass. But comfortable for 24/7 wear? The Oura Ring has it beat by a country mile on sheer wearability.

Sleep Tracking: Where the Oura Ring 4 Dominates

This is Oura's home turf. A 2024 study in Sensors compared both against polysomnography, the clinical gold standard, and the Oura Ring 4 showed no statistically significant difference from lab results across wake, light, deep, and REM stages. No significant difference from a sleep lab. The Smart Sensing 2.0 system uses an 18 pathway PPG sensor array that adapts to your finger's physiology.

The Apple Watch Series 11 added a Sleep Score in watchOS 26. Decent improvement. But it still underestimates wake time and deep sleep compared to clinical measurements. Oura doesn't just tell you whether you slept well, it tells you why, breaking down HRV trends, respiratory rate, and temperature deviations into a Readiness Score that correlates with how you actually feel.

Heart Health: Apple Watch Series 11 Takes This Round

The Apple Watch Series 11 has an FDA cleared ECG detecting atrial fibrillation. Period. Oura doesn't. If cardiac monitoring matters, and for anyone over 50 or with family heart history, it should, this alone might settle things. Apple also added hypertension notifications, analyzing vascular patterns over 30 day periods. Their clinical study caught about 40% of undiagnosed cases, over 50% for stage 2 hypertension.

Important caveat: it won't give you a blood pressure number. It flags patterns, then tells you to buy a cuff. Restricted to undiagnosed users over 22. The Oura Ring 4 tracks resting heart rate at 99.9% reliability with solid HRV and improved SpO2. Good stuff, but no rhythm alerts.

Battery Life: Not Even Close

Oura Ring 4 lasts 5 to 8 days. Larger sizes hit 7-8 days; smaller rings (sizes 4-7) get 4-5 because the battery is physically tinier. Charge via USB C while you shower twice a week. Done.

Apple Watch Series 11 gets "up to 24 hours." Real world with always on display and notifications? You're charging nightly. Which creates an obvious problem for sleep tracking, you need to find another charging window. Most people do the morning routine charge. Works, but it's a compromise the Oura Ring simply doesn't require.

Fitness Tracking and Smart Features

The Apple Watch is a legitimate training companion, GPS, real time heart rate zones, Workout Buddy with Apple Intelligence coaching, 100+ workout types, swimming support. If you run, cycle, or lift and want mid session data, nothing here competes.

The Oura Ring 4 tracks activity passively. Steps, calorie burn, VO2 Max estimates (new with Gen 4). No GPS, no real time display. It tells you whether today's a good day to push hard or dial back. Different job entirely. On smart features, the Apple Watch runs watchOS 26 with 5G, 64GB storage, calls, texts, Apple Pay, fall detection. The Oura Ring has Bluetooth. Syncs to your phone. That's it. Some consider that simplicity a feature.

Oura Ring 4 vs Apple Watch Series 11: Total Cost Breakdown

Real numbers. Oura Ring 4: $349 + $69.99/year membership = roughly $489 over two years. Without the membership, you lose detailed insights, essentially mandatory. Apple Watch Series 11: $399 (42mm) or $429 (46mm). Cellular adds $100 plus ~$10/month. No subscription required. GPS only over two years: $399 flat. Oura is pricier long term. But $6/month for the best sleep tracker available isn't unreasonable.

Do’s and Don’ts

Months of wearing both taught me that most disappointment with either device comes from expecting it to do the other one's job. The table below sorts out which habits get the most from each, and which assumptions lead people to return a perfectly good tracker. Check it against your own routine before you order either one.

FAQs

Does Apple Watch Series 11 measure blood pressure? No. Common misconception. It offers hypertension notifications, analyzing vascular patterns over 30 days to flag possible undiagnosed high blood pressure.

It's the difference between "you slept okay" and understanding exactly which stages were disrupted. Most users find it worth it despite the added cost.

Do I actually need the Oura membership? Practically, yes. Without the $5.99/month subscription, you get basic daily scores only. The membership unlocks sleep stage breakdowns, long-term trends, personalized recommendations, and SpO2 monitoring.

Is the Oura Ring 4 more accurate than Apple Watch Series 11 for sleep?

Yes, backed by clinical research. A peer reviewed study comparing both against polysomnography found the Oura Ring 4's sleep staging showed no statistically significant difference from lab results. The Apple Watch improved with its Sleep Score feature but still underestimates wake time and deep sleep. The 18 pathway PPG Smart Sensing 2.0 system gives Oura a genuine technical edge for overnight biometrics.

Can I use the Oura Ring 4 with Android?

Absolutely. The Oura Ring 4 works with both iOS and Android, which is a major advantage over the Apple Watch Series 11, iPhone only, no exceptions. If you're on a Samsung Galaxy or Pixel, Oura is your best premium health tracker option in this comparison. Same app features on both platforms.

Do I actually need the Oura membership?

Practically, yes. Without the $5.99/month subscription, you get basic daily scores only. The membership unlocks sleep stage breakdowns, long term trends, personalized recommendations, and SpO2 monitoring. It's the difference between "you slept okay" and understanding exactly which stages were disrupted. Most users find it worth it despite the added cost.

Does Apple Watch Series 11 measure blood pressure?

No. Common misconception. It offers hypertension notifications, analyzing vascular patterns over 30 days to flag possible undiagnosed high blood pressure. No actual number like a cuff provides. Apple's study caught about 40% of undiagnosed cases. If alerted, confirm with an actual cuff for seven days.

Which is better for workouts?

Apple Watch Series 11, hands down. Built in GPS, real time heart rate zones, 100+ workout types, swimming support, and AI powered coaching. Oura Ring tracks activity passively, steps, calories, VO2 Max, but has no screen, no GPS, no mid exercise metrics. Oura tells you if you're recovered enough to train. Apple Watch tracks the training itself.

Can I shower and swim with both?

Both handle showers fine. Oura Ring 4 is rated to 100 meters, swimming, snorkeling, saunas. Apple Watch Series 11 is WR50 rated to 50 meters, fine for pool swimming. Neither is meant for scuba.

Is buying both worth it?

If you have ~$750 and take health seriously, wearing both makes genuine sense. Oura handles sleep and recovery; Apple Watch covers daytime fitness, ECG, and smartwatch functionality. They overlap less than you'd think. Several athletes run this dual setup daily.

I've worn both of these for extended stretches, the 46mm Apple Watch Series 11 and the 44mm Galaxy Watch 8, and they're closer in quality than any previous generation. Samsung finally nailed the thinness problem, shaving 11% off the previous model's profile. Apple added hypertension alerts and a proper 5G cellular option in titanium. Neither is a bad buy. But one of them is almost certainly a better buy for you, and that's what this whole comparison is about. I'll break down display, performance, health features, battery, software, and pricing so you can stop doom scrolling spec sheets and just pick the watch that fits your life.

Display Brightness and Screen Quality. Apple Watch Series 11 vs Samsung Galaxy Watch 8

Samsung wins the brightness war outright. The Galaxy Watch 8 pushes 3,000 nits peak brightness, which is a full 50% brighter than the Apple Watch Series 11's 2,000 nit max. If you run outdoors at noon or cycle in direct sunlight, that difference is noticeable, not subtle, genuinely noticeable. I checked my heart rate mid run on both, and the Galaxy Watch 8's screen was readable without shading it with my hand. The Apple Watch needed a slight wrist tilt. That said, Apple's display has a wider color gamut and the always on mode dims beautifully to 1 nit, which is arguably better for sleeping with it on. The 46mm Apple Watch gives you a 2.0 inch display versus the Galaxy Watch 8's 1.47 inch panel on the 44mm model. More screen real estate means more complication space, bigger text, and easier tap targets. If your eyesight isn't perfect, the Apple Watch is noticeably easier to read. Samsung counters with sapphire crystal glass on the Watch 8, though Apple also uses sapphire on its titanium models. The aluminum Apple Watch Series 11 did get more scratch resistant glass this generation, which is a quiet but welcome upgrade.

Processor and Performance, Which Watch Feels Faster?

Samsung made the bigger leap here. The Galaxy Watch 8 runs on the Exynos W1000, a 3nm chip with a 5 core CPU. That's a meaningful architectural jump, apps load faster, transitions are smoother, and the whole interface feels snappier than the Watch 7. Apple kept the S10 chip from the Series 10, which is a 64 bit dual core processor with a 4 core Neural Engine. It's still fast. Buttery fast, even. But it's not new. If you're coming from a Series 9 or 10, the performance difference on the Apple side is essentially zero. Samsung owners upgrading from a Watch 6 or older will feel a much bigger jump. Storage tells a similar story: Apple doubled down with 64GB, while Samsung sticks with 32GB and 2GB of RAM. For offline Spotify playlists and map caching, that extra storage on the Apple Watch is genuinely useful.

Health and Fitness Tracking, The Features That Actually Matter

Both watches throw an overwhelming list of health sensors at you, but the accuracy differences matter more than the feature count. The Apple Watch Series 11 introduced hypertension notifications, a first for any mainstream smartwatch. It won't give you a blood pressure reading, but it'll alert you if your vascular patterns suggest consistently elevated pressure. That's a meaningful health feature, not a gimmick. Apple also keeps ECG, blood oxygen monitoring, sleep apnea detection, and temperature sensing. Samsung's Galaxy Watch 8 counters with its own unique trick: the Antioxidant Index. It measures carotenoid levels in your skin, which correlate with diet quality and overall antioxidant status. Sounds niche, but if you're tracking nutrition alongside fitness, it's surprisingly motivating. Samsung also added Bedtime Guidance, which suggests your ideal sleep time based on your circadian rhythm patterns. In raw accuracy, the Apple Watch Series 11 edges out Samsung on heart rate and SpO2 readings. Samsung's GPS tracking is slightly more accurate for running routes, though. Pick your priority.

Battery Life, Samsung's Clear Advantage

The Apple Watch Series 11 still quotes "up to 24 hours," which is Apple-speak for "charge it every night." The fast charging is excellent, 15 minutes gets you about 8 hours of use, but you're still tethered to that magnetic puck daily. If you want to track sleep without sacrificing daytime battery, Samsung makes that easier. You can shower, sleep, and work out without ever thinking about the charger until the second evening.

No sugarcoating this one. The Galaxy Watch 8 lasts longer. Period. Samsung claims 40 hours with always on display disabled and 30 hours with it on. The 44mm model packs a 435mAh battery, and the 40mm has 325mAh. In my testing, the 44mm Galaxy Watch 8 consistently made it through a full day and into the next afternoon with always on enabled, GPS workout tracking, and sleep monitoring. The Apple Watch Series 11 still quotes "up to 24 hours," which is Apple speak for "charge it every night." The fast charging is excellent, 15 minutes gets you about 8 hours of use, but you're still tethered to that magnetic puck daily. If you want to track sleep without sacrificing daytime battery, Samsung makes that easier. You can shower, sleep, and work out without ever thinking about the charger until the second evening. With the Apple Watch, sleep tracking means you're hunting for a charging window during the day.

Software and Smart Features, watchOS 12 vs One UI 8 Watch

Apple's watchOS runs on the new Liquid Glass interface design, which honestly looks stunning. It's translucent, layered, and feels more modern than anything Samsung offers visually. Siri handles on-wrist tasks well, and the app ecosystem is deeper.

Apple's watchOS runs on the new Liquid Glass interface design, which honestly looks stunning. It's translucent, layered, and feels more modern than anything Samsung offers visually. Siri handles on wrist tasks well, Apple Pay is seamless, and the app ecosystem is deeper. Period. More developers build for Apple Watch first, and it shows in the quality and variety of third party apps. Samsung's One UI 8 Watch on Wear OS 6 is no slouch, though. The big addition is Google Gemini on your wrist, actual AI that can execute multi step actions, not just answer questions. The Now Bar surfaces contextual information without you asking, and Samsung's gesture controls for answering calls and dismissing alarms work reliably. The Galaxy Watch 8 also plays better with Android phones beyond Samsung, it works with any Android 10+ device, though you lose some features without a Galaxy phone.

Compatibility and Ecosystem Lock In

This is the dealbreaker for most people, and it should be. The Apple Watch Series 11 requires an iPhone running iOS 17 or later. Full stop. No Android support, no workaround, no exceptions. If you own an Android phone, the Apple Watch literally cannot function. The Galaxy Watch 8 works with any Android phone running Android 10 or later, though the best experience comes with a Samsung Galaxy device. Samsung Health features, phone to watch continuity, and certain settings sync better with Galaxy phones. But unlike Apple, you're not completely locked out if you switch to a Pixel or OnePlus next year. This also affects resale. An Apple Watch holds value better because iPhone users have no alternative. A Galaxy Watch competes with Pixel Watch, Garmin, and others, so depreciation hits harder.

Pricing and Value, What You Actually Pay

The Apple Watch Series 11 starts at $399 for the 42mm GPS model and $429 for the 46mm. Cellular adds roughly $100, and the titanium model with 5G jumps to $699. Samsung's Galaxy Watch 8 starts at $349 for the 40mm Bluetooth version and $379 for the 44mm. LTE bumps the 44mm to $429. The Galaxy Watch 8 Classic in 46mm starts at $499 with the physical rotating bezel. Dollar for dollar, Samsung gives you more hardware, brighter display, longer battery, 3nm chip, for $50 less at the base level. Apple charges a premium for its ecosystem, software polish, and health features like hypertension alerts. Neither is overpriced for what you get. But if budget matters, Samsung's entry point is friendlier, and you don't lose much in core functionality.

Apple Watch Series 11 vs Samsung Galaxy Watch 8, Who Should Buy Which?

Buy the Apple Watch Series 11 if you own an iPhone, want the deepest health feature set including hypertension monitoring, and prefer a polished app ecosystem where everything just works. The 64GB storage is great for music lovers, and the titanium 5G option is the best premium smartwatch on the market right now. Buy the Galaxy Watch 8 if you're on Android, want longer battery life without compromise, and like Samsung's newer health metrics like Antioxidant Index. The 3nm Exynos W1000 chip is genuinely faster than anything Samsung has shipped before, and the thinner design is comfortable for all day wear including sleep tracking. Honestly? Both are excellent. The ecosystem you're already in should make the decision for you.

Do’s and Don’ts

Before you commit to either watch, run through this quick list of smart moves and avoidable mistakes. These are the practical lessons that come up again and again when people choose between the Apple Watch Series 11 and the Galaxy Watch 8. A minute here can save you a return shipment later.

FAQs

Is the Apple Watch Series 11 worth it over the Series 10?

Honestly, the upgrade is modest. You get hypertension notifications, slightly better battery optimization, and more scratch resistant glass on the aluminum model. The S10 chip is carried over from the Series 10, so performance is identical. If you're on a Series 8 or older, the jump is significant. Coming from a Series 10? You could skip this generation without missing much unless hypertension monitoring is specifically important to you. The 5G titanium option is new and compelling, but that's a $699 commitment.

Does the Samsung Galaxy Watch 8 work with iPhones?

No. The Galaxy Watch 8 requires an Android phone running Android 10 or later. Samsung doesn't offer any iPhone compatibility, and there are no reliable workarounds. If you're an iPhone user interested in Samsung's hardware, you're out of luck, the Apple Watch is your only real option in the premium smartwatch space. Google's Pixel Watch is also Android only, so iPhone users are effectively locked into Apple's ecosystem for wrist wearables.

Which smartwatch has better battery life, Apple Watch Series 11 or Galaxy Watch 8?

The Samsung Galaxy Watch 8 wins battery life convincingly. The 44mm model with its 435mAh battery lasts roughly 30-40 hours depending on always on display usage, while the Apple Watch Series 11 tops out around 24 hours in ideal conditions. Real world use with GPS workouts and notifications usually means the Apple Watch needs a nightly charge, while the Galaxy Watch 8 can comfortably stretch into a second day. Apple's fast charging partially compensates, 15 minutes gives you about 8 hours, but Samsung still holds the advantage here.

Can I use Google Assistant or Gemini on the Apple Watch Series 11?

No. The Apple Watch exclusively uses Siri as its voice assistant. Google Gemini is available on the Samsung Galaxy Watch 8, where it can handle multi step tasks and contextual requests directly from your wrist. Siri on watchOS handles basics well, setting timers, sending messages, checking weather, but it lacks the conversational depth and action chaining that Gemini brings to Samsung's platform. If AI assistant capability on your wrist matters to you, Samsung has a real edge here.

Apple Watch Series 11 vs Samsung Galaxy Watch 8, which is more accurate for fitness tracking?

It depends on what you're tracking. The Apple Watch Series 11 delivers slightly more accurate heart rate monitoring and SpO2 readings based on independent testing. Samsung's Galaxy Watch 8 has better GPS accuracy for outdoor running routes and more consistent elevation tracking. For step counting, both are within 2-3% of each other, close enough to call it a tie. Tom's Guide tested both over 10,000 steps and found the results nearly identical. Sleep tracking is a draw, with Apple offering better sleep stage detection and Samsung providing more actionable sleep coaching.

Is the Galaxy Watch 8 Classic worth the extra $150 over the standard model?

For some people, absolutely. The Classic brings back the physical rotating bezel at 46mm, which is genuinely the best navigation method on any smartwatch. It feels tactile, it's precise, and it works with gloves on, something touchscreens can't match. You also get a slightly larger battery and a more traditional watch aesthetic. But at $499 for Bluetooth and $549 for LTE, you're entering Apple Watch territory on price. If you don't care about the bezel and prefer a thinner profile, the standard Galaxy Watch 8 at $349-$379 is the smarter buy.

Which smartwatch is better for health monitoring in 2026?

The Apple Watch Series 11 has the broader health feature set, including the exclusive hypertension notification system, ECG, blood oxygen, temperature sensing, and sleep apnea detection. Samsung counters with the Antioxidant Index for nutrition tracking and Bedtime Guidance for circadian rhythm optimization. Both offer fall detection and emergency SOS. For serious health monitoring, especially cardiovascular, the Apple Watch has more FDA cleared features. Samsung's health features lean more toward wellness and lifestyle optimization. Neither replaces a doctor, but the Apple Watch is closer to a medical device than any other consumer smartwatch.

Should I wait for the Apple Watch Series 12 or Galaxy Watch 9?

If you need a smartwatch now, buy now. The Apple Watch Series 12 is expected around September 2026, and rumors suggest a blood pressure reading feature (not just alerts) and a thinner design. The Galaxy Watch 9 will likely arrive in July 2026 with iterative improvements. Waiting six plus months for incremental upgrades rarely makes sense unless your current watch still works fine. Tech moves fast, and there will always be something newer around the corner. Both the Series 11 and Watch 8 are mature, capable devices that won't feel outdated for at least two to three years.

I've tested smartwatches from Samsung, Google, and Apple over the past three years, and I keep coming back to the Apple Watch for one reason, it just works without fiddling. I spent real time with the Series 11 running watchOS 26, tested hypertension notifications, pushed the battery through heavy GPS workouts, and compared it side by side with my old Series 10. What follows is an honest breakdown, the good, the meh, and the stuff Apple's marketing glosses over.

What's Actually New in the Apple Watch Series 11

The changelog is short. Apple kept the same S10 chip inside, which says a lot about where they spent their budget this cycle. The aluminum models now use upgraded Ion X glass that's 2x more scratch resistant than the Series 10. After six months of daily wear, gym sessions, yard work, smacking it on door frames, my screen is pristine. My Series 10 aluminum had visible micro scratches within three months. The 5G connectivity uses RedCap technology, a low power flavor designed for wearables. It won't download movies faster, but it provides better coverage where LTE struggled. Battery jumps from 18 to 24 hours quoted. Real world? I get 20-22 hours with always on display and a 45 minute GPS workout.

Apple Watch Series 11 Review: Battery That Finally Lasts

Twenty four hours. Apple finally hit the number that should've been baseline three generations ago. Fast charging delivers 8 hours of tracking from just 15 minutes on the charger, I've tested this before early morning runs when I forgot to charge overnight. Reliable. Low Power Mode stretches to 38 hours, genuinely useful for overnight sleep tracking plus a full next day. The 5G radio doesn't drain noticeably more than LTE in my testing, though heavy standalone cellular use compresses things to 18-20 hours. Good enough. Not remarkable.

Hypertension Notifications: Headline Feature, Mixed Feelings

The optical heart sensor analyzes vascular response to each heartbeat over 30 day rolling windows. If it spots patterns consistent with chronic high blood pressure, you get a notification. Critical distinction: this isn't a blood pressure monitor. No 120/80 reading. It's a screening tool that flags potential hypertension so you visit a doctor. A colleague with diagnosed hypertension confirmed it flagged him within three weeks. FDA clearance covers the US and EU, over 150 countries total. Genuinely useful for the 40+ crowd who might not know they have a problem. But don't confuse it with actual measurement.

watchOS 26: The Software That Makes Upgrades Tricky

Here's the catch. Hypertension notifications and sleep score aren't Series 11 exclusives, they're watchOS 26 features rolling out to Series 9, Series 10, and Ultra 2. If you own any of those, you get the health upgrades free. Workout Buddy, the Apple Intelligence feature that gives spoken motivation based on your fitness history, sounds gimmicky but works better than expected. During a tempo run, it told me my pace was 15 seconds faster than my average and encouraged me to hold it. Specific and timely. The Liquid Glass interface redesign feels smoother, and the wrist flick gesture for dismissing notifications is one of those small things you use fifty times a day.

Apple Watch Series 11 Specs and Pricing Breakdown

Two sizes: 42mm and 46mm. Aluminum starts at $399 GPS only, $499 with 5G cellular. Titanium jumps to $699 with 5G included, available in Natural, Gold, and Slate. The titanium case is 3D printed from aerospace grade powder with sapphire crystal displays. Weight ranges 29.7g to 43.1g depending on size and material, titanium runs about six grams heavier. Display peaks at 2,000 nits, same as Series 10. Dimensions are 9.7mm thick across both sizes. The 42mm fits wrists 130-200mm, the 46mm fits 140-245mm. Go 46mm if your wrist allows it, the extra screen space makes a real difference for notifications and maps.

Series 11 vs Series 10: The Honest Verdict

If you own a Series 10, stay put. Seriously. The Series 10 is hitting all time low prices, and the only hardware differences are scratch resistance, Space Gray, six extra hours of battery, and 5G. Every headline software feature is coming to your watch through watchOS 26. You're paying $399 for a tougher screen. Not worth it. Coming from a Series 8 or older? Now we're talking. You gain the larger display from Series 10, dramatically better battery, crash detection, temperature sensing, sleep apnea alerts, and hypertension screening. The jump from Series 7 to 11 is massive. That's a worthwhile upgrade.

Do’s and Don’ts

Six months of daily wear taught me more than the spec sheet did. This table is the short version, what to do before and after buying the Series 11, and the traps that cost real money. Run through it before you click buy.

FAQs

Is the Apple Watch Series 11 worth upgrading from Series 10?

For most people, no. Both share the same S10 processor, display size, brightness, and core sensors. Hypertension notifications and sleep score are watchOS 26 updates coming to Series 9, 10, and Ultra 2. You're paying $399 for scratch resistance, six extra battery hours, and 5G. Unless you constantly scratch your aluminum watch, the math doesn't work.

How accurate are the hypertension notifications?

The feature has FDA clearance and analyzes optical sensor data over 30 day periods to detect chronic high blood pressure patterns. Users with diagnosed hypertension report it flagging them within two to three weeks. It's a screening tool, not a diagnostic, it tells you to see a doctor, not what your numbers are.

What's the real battery life?

Apple says 24 hours. With always on display, notifications, and a 45 minute GPS workout, I get 20-22 hours consistently. Heavy 5G cellular use drops that to 18-20. Low Power Mode genuinely hits 38 hours. Fast charging gives 8 hours from 15 minutes on the charger.

Should I get aluminum or titanium?

Aluminum starts at $399/$499. Titanium is $699 with 5G included plus sapphire crystal display. If you've scratched previous aluminum models, titanium solves that permanently. The six gram weight difference is barely noticeable. For outdoor athletes or anyone rough on watches, the premium is justified.

Does the Apple Watch Series 11 measure blood pressure?

No. It monitors vascular patterns over 30 day windows and alerts you if those patterns suggest chronic hypertension. No systolic/diastolic numbers. Think of it as a flag that says "go see your doctor," not a replacement for a cuff.

Is 5G on the Apple Watch actually useful?

Only if you use cellular without your phone nearby. RedCap 5G provides better coverage where LTE was spotty, runners and hikers notice the difference. If your phone's always nearby, you won't notice. Check your carrier's coverage map before paying the $100 aluminum cellular premium.