App
P1
Product 1: eufy FamiLock S3 Max Smart...
4.2
The Eufy app was considered capable and feature-rich, with useful controls and setup help, but one reviewer found it sprawling.
P2
Product 2: Aqara UWB Smart Lock U400
4.0
The Aqara app was seen as useful and feature-rich, but reviewers also flagged setup complexity, a Matter-code issue, and a learning curve for customization.
Auto-lock
P1
Product 1: eufy FamiLock S3 Max Smart...
4.7
Auto-lock was viewed as a meaningful convenience and peace-of-mind feature, especially for families that forget to lock up.
P2
Product 2: Aqara UWB Smart Lock U400
4.6
Auto-lock was broadly praised and often described as reliable or well implemented, though one reviewer found Aqara app close-detection sometimes delayed.
Auto-relock after failed attempts
P1
Product 1: eufy FamiLock S3 Max Smart...
4.0
Wrong-try lockout was viewed positively as a useful safeguard against repeated bad attempts.
P2Product 2: Aqara UWB Smart Lock U400
No score yetBattery
P1
Product 1: eufy FamiLock S3 Max Smart...
4.4
The dual-battery design was one of the most praised practical features, although heavy camera use made one reviewer doubt the advertised runtime.
P2
Product 2: Aqara UWB Smart Lock U400
4.3
Battery feedback was mostly positive for USB-C charging, removable/rechargeable design, and long runtime, tempered by concerns about spare or replacement batteries.
Build quality and durability
P1
Product 1: eufy FamiLock S3 Max Smart...
4.7
Build quality drew strong praise, with reviewers describing the lock as robust, durable, and safe-like despite its size.
P2
Product 2: Aqara UWB Smart Lock U400
4.7
Build quality was viewed positively, with reviewers describing a step up from earlier Aqara locks and solid, well-made hardware.
Camera and doorbell performance
P1
Product 1: eufy FamiLock S3 Max Smart...
4.2
Camera and doorbell performance was mixed-positive: daytime video, field of view, and the indoor screen drew praise, while low-light video, audio, and doorbell-button expectations were caveats.
P2
Product 2: Aqara UWB Smart Lock U400
4.5
Camera and doorbell integration was described as practical when paired with Aqara or Apple Home video devices, letting users see visitors and unlock from one screen.
Door-sense
P1
Product 1: eufy FamiLock S3 Max Smart...
3.8
Door-sense received qualified praise because it can infer door state without a separate sensor, though with some edge-case caveats.
P2
Product 2: Aqara UWB Smart Lock U400
4.7
Door-sense evidence was limited but positive, centered on the built-in gyroscope knowing when the door closes so it can lock without an added sensor.
Door compatibility (deadbolt fit)
P1
Product 1: eufy FamiLock S3 Max Smart...
2.5
Door fit/usefulness is context-dependent: glass, windowed, screen, or storm doors can reduce the value of the camera and interior display.
P2
Product 2: Aqara UWB Smart Lock U400
4.3
Door fit flexibility was helped by adapters/cross-bore support, with reviewers calling the physical fit detail useful for nonstandard openings.
Feature additions via updates
P1Product 1: eufy FamiLock S3 Max Smart...
No score yet
P2
Product 2: Aqara UWB Smart Lock U400
4.5
Feature-update evidence was limited but positive, with one reviewer saying Aqara is good about firmware updates.
Fingerprint
P1Product 1: eufy FamiLock S3 Max Smart...
No score yet
P2
Product 2: Aqara UWB Smart Lock U400
4.7
Fingerprint access was consistently praised as quick, accurate, consistent, or convenient, especially as a backup when UWB is unavailable.
Finish durability
P1
Product 1: eufy FamiLock S3 Max Smart...
4.2
Finish durability was only lightly covered, but one reviewer said the black metal casing still looked good after use.
P2
Product 2: Aqara UWB Smart Lock U400
4.2
The exterior finish earned a positive note for resisting fingerprints better than expected.
Hub requirement
P1
Product 1: eufy FamiLock S3 Max Smart...
2.7
HomeBase dependence was a downside when reviewers wanted facial recognition or the most advanced alerts.
P2
Product 2: Aqara UWB Smart Lock U400
4.0
Hub requirements were mixed: reviewers liked avoiding an Aqara hub in Apple Home, but still emphasized the need for a Thread border router for full functionality.
Industrial design
P1
Product 1: eufy FamiLock S3 Max Smart...
4.2
Industrial design was seen as modern and premium, though several reviewers noted that the lock is large or visually high-tech.
P2
Product 2: Aqara UWB Smart Lock U400
3.9
Industrial design was the most mixed area: reviewers liked the sleeker, more mature, minimal look, but others called it bulky, plain, or plastic-looking.
Installation and Setup
P1
Product 1: eufy FamiLock S3 Max Smart...
4.3
Reviewers generally found setup straightforward and app-guided, though one pre-release unit caused connection and install friction.
P2
Product 2: Aqara UWB Smart Lock U400
4.2
Installation was usually described as straightforward and fast, with several reviewers finishing quickly, though a few noted tight wiring, small screw holes, or a latch-area snag.
Key override reliability
P1
Product 1: eufy FamiLock S3 Max Smart...
4.2
Reviewers treated the physical key override as a useful fallback for emergencies or users who prefer non-smart access.
P2
Product 2: Aqara UWB Smart Lock U400
4.3
Reviewers liked retaining a physical-key fallback, framing it as a useful mechanical backup rather than a compromised smart-only design.
Keypad
P1
Product 1: eufy FamiLock S3 Max Smart...
4.5
The keypad was generally praised as responsive, visible, and easy to use, with scramble-code support helping privacy.
P2
Product 2: Aqara UWB Smart Lock U400
4.1
The keypad was generally usable and responsive, but reviewers also found that it could take extra taps or touches to wake in some cases.
Keyway quality
P1
Product 1: eufy FamiLock S3 Max Smart...
2.8
The hidden keyway cover was the weakest physical detail, with one reviewer finding it hard to reseat securely.
P2
Product 2: Aqara UWB Smart Lock U400
4.3
The keyway/cylinder was viewed positively because the reviewer liked that it could be rekeyed rather than forcing a full lock replacement.
Lock/unlock speed
P1
Product 1: eufy FamiLock S3 Max Smart...
5.0
Lock/unlock responsiveness was excellent in testing, especially with voice commands.
P2
Product 2: Aqara UWB Smart Lock U400
4.8
Lock/unlock speed was one of the strongest themes, especially with UWB; reviewers described fast reactions, instant Home app response, and few delay caveats.
Locking reliability
P1
Product 1: eufy FamiLock S3 Max Smart...
5.0
Locking reliability was consistently strong in the reviews that tested repeated lock/unlock behavior and routines.
P2
Product 2: Aqara UWB Smart Lock U400
5.0
Locking reliability was strongly praised, with reviewers repeatedly reporting flawless, rock-solid, or consistently smooth hands-free unlocking.
Notifications
P1
Product 1: eufy FamiLock S3 Max Smart...
4.5
Motion and doorbell notifications were mostly praised for speed and accuracy, with one reviewer noting a small delay.
P2
Product 2: Aqara UWB Smart Lock U400
4.6
Notifications earned praise for adding Apple Watch/iPhone confirmation and a quick relock option after UWB unlocks.
Palm vein recognition
P1
Product 1: eufy FamiLock S3 Max Smart...
4.7
Palm vein recognition was the clearest strength, repeatedly described as fast, reliable, convenient, and easier than fingerprints, with minor caveats about angle and unlock-only use.
P2Product 2: Aqara UWB Smart Lock U400
No score yetPhysical attack resistance
P1
Product 1: eufy FamiLock S3 Max Smart...
4.4
Physical attack resistance had limited but positive evidence, with reviewers pointing to solid construction and tough security design.
P2
Product 2: Aqara UWB Smart Lock U400
2.8
Physical attack resistance drew a caveat: the reviewer appreciated certification but clearly wished the U400 had a stronger Grade 2 rating instead of Grade 3.
Pick/drill resistance (if rated)
P1
Product 1: eufy FamiLock S3 Max Smart...
4.5
Pick resistance was praised in reviews that discussed the encrypted cylinder or difficulty of picking the lock.
P2Product 2: Aqara UWB Smart Lock U400
No score yetRemote access
P1
Product 1: eufy FamiLock S3 Max Smart...
4.5
Remote access had limited evidence but was described as quick and reliable.
P2
Product 2: Aqara UWB Smart Lock U400
3.8
Remote access was useful when configured, with one reviewer praising fast remote unlock and another noting Aqara-app remote control needs an Aqara hub.
Security features (encryption)
P1
Product 1: eufy FamiLock S3 Max Smart...
4.5
Security encryption evidence was limited but positive, centered on the encrypted lock cylinder adding protection.
P2
Product 2: Aqara UWB Smart Lock U400
4.8
Security features were praised around UWB precision, encryption-related safeguards, and prevention of unintended inside unlocks or relay-style weaknesses.
Smart-home integration (Alexa, Google, Siri, HomeKit, Matter, Thread)
P1
Product 1: eufy FamiLock S3 Max Smart...
3.5
Smart-home integration was the most split area: basic Matter, Alexa, Google, and HomeKit control worked, but advanced lock, camera, and palm features often stayed inside Eufy.
P2
Product 2: Aqara UWB Smart Lock U400
4.8
Smart-home integration was a major strength, with reviewers praising Apple Home, Matter over Thread, responsiveness, major ecosystem support, and future-looking compatibility.
Touchscreen
P1
Product 1: eufy FamiLock S3 Max Smart...
5.0
Touchscreen/keypad usability was supported by positive comments about responsiveness and backlighting.
P2
Product 2: Aqara UWB Smart Lock U400
3.2
Touchscreen evidence was mixed, with one reviewer naming wake-up attempts as the main complaint.
User access management
P1
Product 1: eufy FamiLock S3 Max Smart...
4.5
User access management was praised for making family access easy and supporting different time slots.
P2
Product 2: Aqara UWB Smart Lock U400
4.3
User access management was positively reviewed for adequate household limits, more granular Aqara controls, and approachable local fingerprint setup.
Value and Price
P1
Product 1: eufy FamiLock S3 Max Smart...
3.7
Value was mixed: reviewers repeatedly called it expensive, but some felt the all-in-one lock, camera, and doorbell package justified the premium.
P2
Product 2: Aqara UWB Smart Lock U400
4.3
Value sentiment was favorable but conditional: reviewers called it worth the upgrade or routine-changing, while also noting the price can feel high.
Voice control
P1
Product 1: eufy FamiLock S3 Max Smart...
4.8
Voice control worked quickly where tested, especially through Alexa, Siri, or Google lock commands.
P2
Product 2: Aqara UWB Smart Lock U400
4.2
Voice control received limited but positive evidence, with a reviewer saying they wished they had the supported voice-control lock routine at home.
Weather resistance
P1
Product 1: eufy FamiLock S3 Max Smart...
4.2
Weather resistance received limited but positive support tied to the lock’s durable construction for harsh conditions.
P2
Product 2: Aqara UWB Smart Lock U400
4.8
Weather resistance came across well: reviewers said it could face the elements, and one real-world test cited rain, snow, ice, and no missed performance.
Wi-Fi
P1
Product 1: eufy FamiLock S3 Max Smart...
4.6
Wi-Fi performance was positive overall, with quick setup, steady connectivity, and claimed responsiveness from Wi-Fi 6 support.
P2Product 2: Aqara UWB Smart Lock U400
No score yet