Owed to a repair, I had to be without my watch for a couple weeks. In that time I learned what the 2 primary features were that I can no longer live without (exaggeration):
1) checking the time without pulling my phone out of my pocket
2) checking notifications - to see whether a call, email or text warranted immediate attention - without pulling my phone out of my pocket
If you do both of the above frequently, then that alone would justify the AW imho. I also love the fitness tracking, but that could be had elsewhere. So could notifications TBH. Wrapped together in an Apple package though? That makes it all worthwhile.