I'm using it as a fitness tracker. I'm tracking steps with Pedometer++, booking exercise with the exercise app, tracking weight with MyFitnessPal, and seeing the results with a Withings Smart Scale every morning talking to MyFitnessPal. I've lost 12 pounds so far, and I'm motivated now to lose 28 or 38 more. I'm also using it as a sleep tracker.
It's an excellent companion device for driving. I like the taps on the wrist for directions.
I like the seamless integration with the Apple ecosystem.
The battery life could be better, but since I'm sitting at a desk all day, periodically I'll charge it to keep it near 100%. I'll also charge it when I'm watching Netflix at the end of the day. I haven't yet had a day when I'm away from power for an extended period of time. That'll happen later this year when I go to football games.
I dont mind having to bring my phone with my everywhere to get the most out of the watch, since I do that anyway.
I'm able to use it as a sleep tracker since I don't need to charge it overnight. That's been fantastic.
Some of the apps have been great, some are still a work in progress.
I'm still very happy with it