I played since day one, took a time out til battlegrounds came out, came back had a little fun in AV and decided to take timeout again.
TBC made it a little bit fun again and then I realised it was a bigger grind than before for rep and such, Karazhan drops are useless, really should be more drops per boss so you dont have to spend your life in there.
If you have absolutely no life outside wow then its def a game worth playing, but if you do have a life dont start playin otherwise it will suck the life outta you and it does make changes in your personality, ie moody and generally miserable.