GE is really, really fun for about a week - Then it becomes unbearably grindy. One of my IRL friends was apparently the leader of the biggest guild on one of the NA servers or something retarded like that, he said the game was pretty much a shitfest at endgame play, it's all just super grinding, getting OP characters, then ohko-ing everyone you can click on in PvP.
I wouldn't really consider Guild Wars much of an MMO, tbh. It reminds me more of action games like Diablo 2, since it's all instanced small group play, instead of "HOLY SHIT 200 GUYS ON SCREEN FARM ALL THE SPIDERS YOU CAN MADNESS!". But I am also biased, since my uncle's one of the art guys at arena.net :v
I started playing DDO lately, and it's kind of fun. It sort of reminds me of GW in the sense that all the missions and such are instanced, but it's moderately entertaining, especially if you're familiar with the tabletop game, they did a better job than I expected to at staying true to the tabletop game, but still having everything be useful.