Oura Ring 4
The most discussed AI health ring on Reddit, with r/ouraring's 176,800 members consistently rating it the best sleep tracker available in any form factor. Uses machine learning to generate a daily Readiness Score from 20+ biometrics and detects illness 1-3 days before symptoms via overnight temperature tracking.
Key Features:
- ✓Readiness Score: daily 0-100 AI synthesis of HRV, resting HR, skin temperature, and sleep data
- ✓Illness detection: temperature spike alerts 1-3 days before cold and flu symptoms appear
- ✓Sleep staging: detailed nightly breakdown of light, deep, and REM sleep
- ✓Stress meter: tracks sympathetic nervous system activity throughout the day
- ✓Period prediction: cycle tracking with AI-assisted ovulation estimates
Pricing:
$299-$499 ring + $5.99/mo or $69.99/yr membership
Pros:
- + Best-in-class sleep tracking per consistent r/ouraring community consensus
- + Ring form factor is far more comfortable overnight than any wrist tracker
- + Illness detection has helped members catch COVID-19 and colds 1-3 days early
- + 7-day battery eliminates daily charging disruptions to sleep data
Cons:
- - $5.99/month membership locks trends, insights, and illness alerts behind paywall
- - Workout and activity tracking far less accurate than Apple Watch or Garmin
- - Step counter widely criticized as unreliable in r/ouraring threads
Best For:
Anyone who prioritizes sleep quality, recovery tracking, and early illness warning over workout metrics, and is comfortable with the subscription model.

