I've been playing Guild Wars for a few weeks now and I must say it's a great game and unlike any other MMORPG I've played before (coming from EverQuest & Star Wars Galaxies). I would also compare Guild Wars with games like Neverwinter Nights and Dungeon Siege more than I would other MMORPG's to. Some of the reasons being that in Guild Wars it's easy to find a group, do a quick mission and feel like you character has advanced in the game world. Even if you can't find a group you can always play it alone with the aid of AI henchmen if you really want (although I wouldn't recommend doing that if you can help it).
Now that I've hit level 20 I'm hoping that the game play will change, not that I'm bored with it. I should now be able to concentrate more on questing for items, helping my guild and competing in player vs player matches (PvP). I'm not sure what to expect yet but I hope that the game can keep me interested for a little bit longer.