Design and display
The Mi Smart Band 4 has a capsule-shaped body that fits in a silicone strap. It has a 0.95-inch AMOLED display that looks dazzling and is definitely one of the most intuitive displays in its segment. It has good brightness levels that makes it easy and convenient to read content on band’s screen in bright outdoors.
The band has comfortable straps and its light-weight build makes it easy to wear and carry all day long. However, its design seems old-fashioned. The band’s home button, which you can use to navigate across choices, sits at the bottom of the screen. To charge the band, you need to take the band’s body out and thrust it into the charger dock. And herein lies its first problem. The capsule doesn't fit the charger well and keeps popping out which can be very frustrating. The only saving grace is you won't need to charge it too often anyway because of its impressive battery life. Xiaomi claims the band can go on for 20 days on a single charge, but there's a catch here, most of the basic features of the fitness band are disabled by default, presumably to keep up the battery life. To be fair, despite manually turning on most of the features, you can still expect the band to run for two weeks on a single charge, which takes less than a couple of hours to accomplish.