If you're in the market for a fitness tracker, you're more than likely hoping to modify your health behavior - whether it's remembering to walk more, tracking how often you work out, or making sure you're working out appropriately hard when you do.

14-day battery life; Bright; colorful screen; Feature-packed at rock-bottom price

Limited types of exercises tracked; Sleep tracking is not very accurate; Mi Fit app provides few actionable bits of advice

The Xiaomi Mi Band 4 delivers fantastic value and features. Upgrades over its predecessor include a color OLED display with significantly improved outdoor viewability and a higher resolution too.

Very cheap; Slimline design; Heart rate monitor

No GPS; No multitasking apps; Doesn't auto-stop tracking

Coming in at half the price of the cheapest Fitbit, Xiaomi's latest Mi Smart Band 4 offers activity-, health- and sleep-tracking at an incredible £34.99. The enhanced colour AMOLED panel alone makes it worth the upgrade, though it won't entirely replace a smartwatch or smartphone for notifications,...

At $40, should you buy the Xiaomi Mi Band 4 or pay double that for a comparable device from a competitor...

Low price point Accurate fitness; health; and sleep tracking Connected GPS is a big plus 20-day battery life Plenty of smart features and customization options

Mi Fit app won't be everyone's first fitness app choice Heart rate sensor struggles with high-intensity workouts

The Xiaomi Mi Band 4 now sports a 0.95-inch display with 120×240 pixels resolution. It also sports a 135mAh battery along with a similar 20-day battery backup claim. For connectivity, Xiaomi has added Bluetooth 5 in the new version of the fitness band.

The below image seems to show that the Xiaomi Mi Band 4 will have a 0.95-inch full colour OLED display, with a tempered glass cover rather than plastic. This is a big improvement from the monochrome display of previous devices in the range, and should make it far more attractive to use - but we...