Fitbit's Charge 2 is the heir to the fitness gadget company's most popular fitness tracker, the Charge HR. The latter has been my personal favourite with its accurate step-tracking and heart rate monitoring abilities. But it is looking dated with new releases from the likes of Garmin, Samsung and even Apple.

The Charge 2 seems like a blend of Fitbit's Surge, Alta and Charge HR. But it looks sleeker than them with its silver metallic sides and a bigger Oled monochrome screen that is four times larger than its predecessor's. A lone button sits to the left of the display.

You can now tap on the display to view various fitness statistics, such as steps taken, calories burned, floors climbed and heart rate. And with the bigger display, the date and time stay on the top with the statistics shown below.

Its rubber strap (black, version reviewed) is easy to put on, and comfortable to wear. But unlike the Charge HR, the Charge 2's rubber straps are swappable. Owners will soon be able to buy other rubber straps ($49.95 each), as well as leather ($109.95) and special edition metallic straps ($298).

The Charge 2 now has the ability to display notifications when paired with a smartphone. It can also track your running distance via your smartphone's GPS sensor. But it would have been better if it had built-in GPS like the Samsung Gear Fit2.

Another one of its new features is Relax, which is similar to Apple watchOS 3's Breathe. It brings you through a session on deep breathing to help you, well, relax.

Charge 2 automatically tracks runs, aerobic workouts and elliptical sessions. But you can also start a workout manually and choose which workout you want, like treadmill running or weight training.

The automatic sports tracking feature works well in detecting walks and runs, provided you walk or run for more than 10 minutes at least.

However, I found my running distance readings increasing by more than 20 per cent without GPS. When connected with my iPhone 6s Plus's GPS, the readings came to within 2 per cent of the actual distance.

The Charge 2 also does a great job of tracking fitness statistics and sleep. Results of my steps taken with the Charge 2 differed by less than 1 per cent from my calibrated Charge HR.

There is no need to manually trigger the sleep-tracking mode. The Charge 2 does this automatically and can detect when I am awake, having a restless sleep, or in deep slumber. It was pretty accurate at pinpointing the time when I woke up in the middle of the night to use the bathroom.

However, heart rate measurements can differ by up to 10 beats per minute from results taken with my Apple Watch Series 2 and my TomTom Spark GPS watch.

If you have previous Fitbit products and think you can use one of those cables with the Charge 2, you would be wrong. You need the bundled proprietary USB cable to charge the device. It is not a deal-breaker but is certainly a hassle.

Another downer is that the Charge 2 is only splash-resistant. So, you can wash your hands or jog with it, but not swim with it. For swimming, you will need the upcoming Fitbit Flex 2.

Like its predecessor, Charge 2's battery life is around five days, or six days if you are not running or do not have too many notifications. Pretty good for a fitness tracker with a display.

•Verdict: Apart from lacking GPS and better water resistance, the Fitbit Charge 2 is easily the most well-rounded fitness tracker on the market.