The Good : A bright display, onboard GPS and waterproof to 50 meters. Integration with Nike+ Run Club. Comfortable strap and comes with two exclusive Nike watch faces.
The Bad : GPS battery life is short. No altimeter for measuring elevation. Workout data can't be exported to other services. Lacks always-on display.
The Bottom Line: If you're a loyal Nike user, this is the Apple Watch to get, but it's really just an Apple Watch Series 2 with a few minor changes. There are cheaper alternatives for pure fitness and run tracking.