The Fitbit Charge 2 comes with a built-in heart rate monitor (so the more expensive HR option is gone this time), as well as something the company calls 'connected GPS'. This means that when the wearable is connected to your phone, it will be able to use that device's location information to record a map of your route and give you real-time stats like pace and distance.
Like Apple, Fitbit now seems to be a fan of breathing exercises, since it's providing some in the Charge 2. The wearable tracks multiple sports such as running, biking, and weightlifting, and it automatically recognizes the activities you're performing. It gives you reminders to move, automatically tracks your sleep (with silent alarm functionality), and it still works with computers as well as Android and iOS devices.