I would imagine it depends on what you're looking for.

A number of GotWoot'rs play Guild Wars. Soon, I'll be one of them as I purchased the game a few days ago. I have not even installed it or opened it, for that matter as of yet, though. A perk to Guild Wars which should quickly attract you, is the fact that there are no monthly fees. It isn't a pay-as-you-play game. One fee for the game, and you're good to go. Just like purchasing a game for your PS2 or X-Box. From the few I know that have played it, they've enjoyed it. There is also a thread for it in this section - you may want to read that over for more details.

City of Heroes is the first and only MMORPG I've ever played. I'm a comic nut, so I was instantly sold on creating my own Superhero. From MMORPGs I have seen, in regards to character creation, City of Heroes / Villains is definitely among the best and most creative with near limitless possibilities. Some things stick out more than others, and just seem much "cooler," so you'll see someone with the same medieval helm or Iron Man helmet, but it's unlikely you'll see an exact clone of a character unless done with that intent.

The game content for CoH does tend to get repetitive, as I would imagine with a lot of MMORPGs, as you're grinding between levels. There is little to no end game content. Although, you do unlock two Epic character types to play with once you reach the level cap. They're pretty sweet. They capture the comic feel and element pretty well, and with the City of Villains release, I truly only expect it to get much, much better.

City of Heroes is pretty cheap right now. I believe something like $19.99 or $29.99, with the first four to six weeks free. If you can spare that, I'd definitely suggest giving it a run through and seeing how you feel about it. If you need to know anything else about it, shoot a post here. I troll a lot, so I'll respond accordingly as I see updates to this topic.

EDIT: Funnily enough as well, a lot of City of Heroes players are former World of Warcraft players who were displeased or extremely bored with the game. On the server broadcast channel, I often see people discussing their numerous reasons for defecting to the superhero side.