The Xiaomi Mi Band fitness trackers are popular and that's down to the combination of useful activity tracking features and affordable prices.

With the Xiaomi Mi Band 3 now out in the wild - our review is underway at the moment - we thought it would be interesting to compare this to the wildly popular Mi Band 2 from a couple of years ago.

The Mi Band 3 brings a couple of new features to the table, but is it worth buying if you already own a Mi Band 2? Read on below to find out which will be the better fitness tracker for you.

Design and display

To the untrained eye, it's unlikely you'll notice a major design change between the Xiaomi Mi Band 3 and its predecessor. Both are thin and light activity bands that wrap around your wrist with a silicone strap.

There's a small fitness tracker inside each that can be popped out of the bands and put into other ones if you want, for example, a different design at different points in your day.

Both trackers come in multiple color options for the bands, plus there's a large amount of third-party bands you can get, so there's a variety of different designs overall.

The Xiaomi Mi Band 3 is a touch longer (it has a bigger display) but that's not a major design change that will alter the way you use the fitness tracker. It's still notably light and won't strain your wrist.

In terms of screen, both offer OLED displays that are only black and white. Each is small, but the Mi Band 2's is by far the smallest at 0.42 inches, while the Mi Band 3 almost doubles that to 0.78-inches.

The Mi Band 3 has a much better display with a resolution of 128 x 80 (the Mi Band 2 is just 72 x 40) as well as touchscreen functionality. But while only the newer model has a touchscreen, both have a touch key below the screen.

Xiaomi's screens aren't going to rival the Samsung Gear Fit 2 Pro any time soon, but if you're looking for the better of these two products in terms of the design and display you'll have to opt for the Mi Band 3.

Fitness

Xiaomi Mi Band 3

Xiaomi has packed lots of fitness tools into both the Mi Band 2 and Mi Band 3, but the newer device is better.

Both trackers will keep an eye on your daily step count and your sleep quality, and all of that data will appear in the Mi Fit app that you'll be able to download to your smartphone.

There's also a heart rate monitor on both fitness trackers that will keep an eye on your beats per minute, but you don't get GPS features on either tracker.

While the Mi Band 2 is water-resistant, the company doesn't actively recommend it for swim tracking like it does for the Mi Band 3. If you want a tool to track your swims, the Mi Band 3 won't be the best but it will be better than nothing and much better than the Mi Band 2, which isn't suited for pool use.

Specs and battery

Xiaomi Mi Band 2

One version of the Xiaomi Mi Band 3 comes with NFC functionality, and that allows those in China to use the Xiaomi Pay service. That's not available outside China, but Xiaomi may one day bring the service to other countries.

Most versions of the tracker don't have NFC though, so that probably won't be a major upgrade you have to worry about.

The Xiaomi Mi Band 3 also comes with a more reliable connectivity tech in the form of Bluetooth 4.2 (compared to Bluetooth 4.0 on the Mi Band 2).

Officially Xiaomi says the Mi Band 3 and 2 are both meant to last up to 20 days, and that depends on how much you'll be using features on the tracker. After a week of usage we found the Xiaomi Mi Band 2 still had 85% battery left - that's better than what Xiaomi estimates.

We have yet to complete our testing with the Mi Band 3, but we hope it will offer a similar level of battery life to the last-gen device.

Price

Truth is, both the Xiaomi Mi Band 2 and Mi Band 3 are impressively cheap considering what each can do. The Mi Band 3 is newer, so is a touch more expensive, but it's still a very affordable price.

It's on sale for 179 Chinese yuan (about $30 / AU$36) and you can buy it in the UK right now for £23 from Gearbest. The Mi Band 2 launched at £28/$35/AU$50 but in the UK we've seen the price drop to around £20, so it's only a touch less than the newer product.

Takeaway

These products are so closely priced that we think it's a no-brainer to go for the Mi Band 3.

There may not be much reason to upgrade to the Band 3 if you already own and like the Xiaomi Mi Band 2, but if you're buying a new one outright and you can find it, go for the more recent tracker to get that better screen and waterproof design.