I found this bad. I tried it back in....2004? Maybe? I thought it was good, but never had the time to play it.
As expansions came out, I became more angry about me not having as much time. Eventually, around level 35 because I was almost never able to play, I quit. Soon afterwards, I started a new account and got this new char to level 35 in a few months. That was fast for me.
I finally quit and, about a year later, created a new character, which got to level 35 in a month.
As I progressed, I found the game gradually getting more boring, even though now I had the time for it. Also, I've never been higher than level 35 due to WoW becoming boring and more interesting games (I got TF2 on the PC a little before that).
Overall, it's good if you have time and don't get bored by doing the same thing repeatedly. I hate grinding. WoW is almost entirely grinding. For some reason Guild Wars interests me more. Don't ask me why, it just does.