My boyfriend loves LotRO, and it's one of the few MMOs that I can get him to try and enjoy. He hated DDO (don't know why, honestly), Ryzom does not have many quests, Wakfu was enjoyable for him but the lack of quest-story content turned him off (while I enjoyed it, and then I saw the terrible cash shop model they implemented at launch), Star Trek Online was annoying (I liked it for about 2 months but I think he's right here), Everquest 2 was boring, and so on. The moral here is I decided to play LotRO with him until the reboot of FFXIV (he took one look of the UI and immediately said, "Uninstall this, please.").
I love LotRO, too. I hate LotRO's grind, however, but that grind is diminished by how much my boyfriend gets into playing this game. He teases me that I should think of it as grinding skills like in Ryzom or Ultima or the Elder Scrolls, but it's not grinding skills, it's grinding commendation essentially, and that bit is annoying to me until I slow down and learn to take it easy, do a dungeon or two with him, and enjoy myself.
So I am playing LotRO at the moment, and instead of the reaction of '"Not another MMO!" it's "Yay! LotRO!" at my house, as he eagerly jumps in on his characters and learning that I decided to start over again (yet again), he switches from the server with 200 plus gold and pre-Rohan maxed characters to my new server just to run around with me again.
I got to say that alone is very engaging. I wonder if my boyfriend is the only person that LotRO inspires so much loyalty in, or if there's a bunch of LotRO people out there just as enchanted by cosmetic armor, legendary weapons, player made music, story-driven questing, and endless freaking grind as he is.