I've played both WoW and LOTRO, however I never really liked WoW. Lord of the Rings Online is a really great MMO with an awesome community. Really, I think the community is what set the game apart from any other MMO I have ever played.
People literally role-play in this game. In the few servers that I actually played on during the beta I noticed that almost no one talked out of context (unless they used a specific chat feature to talk out of role-playing context). It made the game far more enjoyable, and not to mention it made forming fellowships and making your own adventure a lot more fun than just creating a regular guild or clan.
One thing that seems to be a huge repeating factor in almost every single MMO is the constant grinding of XP and never ending satisfaction of repetition to better your character. However, I really didn't notice any repetition with LOTRO, as it was one of the very few games where the quests were actually interesting, entertaining and different. Sure it had it's "go out and kill 5 bears and bring me back their hides", but those were more just for getting some quick cash.
All in all I'd recommend the game; however, I missed out on my opportunity to get the $9.99 monthly fee rather than the $15.00 a month or whatever it currently is now. I don't really have the money to dish out for an MMO at the moment, but I have assured myself that it will be on my soon to purchase list.
I hope that helped your decision