I played WoW for about a year, stopped, then played for 6 months.
It's more of the same the higher up you go.
AOC is the new kid with the flashy graphics and some nifty gore. However it's not finished. I played, and cancelled after the first month. It's also a very spec demanding game.
The combat was more fun in AOC, but I think overall WoW is put together better with years of playtesting and patches. I found the first 20 levels or so the most fun, so if you're not liking it after 15 days, then you probably won't like in the long run.
AOC's first 20ish levels are like an RPG. It's a self contained storyline for you as you progress. It's a pretty polished experience with everything voice acted. Though after lvl 20, and once you enter the open world, the voice acting stops and it turns in to something very different.
I recommend seeing which one your friends like and going with that. Whichever game will be 1000x more fun with others you know playing.