
Polar H9
Score: 83/100
Xiaomi Mi Smart Band 10
Score: 79/100Rankings

The Polar H9 is a chest-mounted ECG heart-rate sensor offering exceptional accuracy and a 400-hour battery life. Its main trade-off is the lack of onboard storage and reliance on a replace-once coin cell battery. Ideal for athletes who need precise data across multiple sports and appreciate dual-protocol connectivity.

The Xiaomi Mi Smart Band 10 (2025) Global Version is a budget-friendly fitness tracker featuring a 1.72-inch AMOLED screen, 21-day battery life and comprehensive sport tracking including accurate swim metrics. Its main limitations are the lack of standalone GPS and a less robust band clasp. It is best for cost-conscious users who want long endurance and a bright display for everyday activity monitoring.
| Attribute | ![]() | ![]() |
|---|---|---|
400 hours | 504 hoursbest | |
| ↓ lower better | 60 g | 27 gbest |
— | 110,240 pxbest | |
— | 1.72 inbest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | ![]() | ![]() |
|---|---|---|
Battery & Power(1) | ||
Battery Life (hours) | 400 hours | 504 hours |
Build & Design(2) | ||
Weight (g) | 60 g | 27 g |
Water Resistance (IP Rating) | IP68 | 5ATM |
Connectivity(1) | ||
Bluetooth Version | Bluetooth LE | 5.4 |


Products in the top-left offer the best value (high score, low price).

Editors and CrossFit-focused reviewers consider the Polar H9 the best-value chest strap, emphasizing its precise ECG tracking, dual-protocol connectivity, and underwater capability.

Professional reviewers commend the Smart Band 10 for its sizable, ultra-bright AMOLED screen, impressive 21-day battery, and highly accurate heart-rate and swim tracking. The addition of an electronic compass and a linear-motor haptic system are seen as meaningful upgrades that elevate the device above its predecessor, while the extensive sport mode library adds versatility. Criticisms focus on the lack of built-in GPS, occasional clasp durability issues, and the hit-or-miss nature of auto-detect workouts, as well as the absence of medical-grade sensors.
Everyday users consistently praise the band's long battery life, bright display, and reliable step, heart-rate, and sleep tracking. Swimmers especially value the 96 % lap-count accuracy and underwater HR broadcast. Common complaints revolve around the missing GPS, unreliable band clasp, and limited smart-phone-only notifications, with many noting that auto-detect workouts can be erratic.
“1.72-inch AMOLED display with 1500 nits peak brightness provides excellent outdoor visibility.”

“No built-in GPS requires a connected phone for location tracking during outdoor activities.”
