There are plenty of decent smart wearable devices on the market that can alert you when you have notifications and track activity. Not too many of them are compatible with iOS, Android, and Windows Phone though. Microsoft Band is different. It is powered by Microsoft Health and helps you track your heart rate, steps, calories burned, and sleep quality.
Microsoft Band helps you get guided workouts, track your heart rate, map your run, and track your sleep. You can use it to monitor e-mail, get calendar alerts on your wrist, and time your laps. The device is also Cortana friendly. Microsoft Band works with RunKeeper, MapMyFitness, and other service providers.