The Apple Watch is capable of doing a lot of things, including keeping you fit and active. Ever since I first got one, I have been obsessed with keeping track of my steps, heart rate, active calories, and number of minutes exercising each day.
I found that the workout app that comes with the watch is great because it is set up to track all different kinds of workouts including running, walking, cycling (indoors and outdoors), elliptical machine, stair master, rowing machine, and other. Although this app isn't much different than any of the iPhone apps you can download off the App Store (MapMyFitness, Nike+ Running, Strava etc.), the advantage is that I never have to deal with carrying my iPhone with me while I am working out. Plus I can answer phone calls from the watch itself if someone happened to be calling me while I was working out.
The thing that the Apple Watch could use improvement on is with the heart rate monitor. It only takes my heart rate randomly throughout the day and is very inconsistent. If there was a way to get it to consistently monitor my heart rate so that I could really know how high and how low my pulse gets throughout the day I would be in fitness heaven.
Overall though, from a fitness standpoint, the Apple Watch will definitely be a great asset for reaching a lot of different kinds of fitness goals (not all though).