This game is very, very similar to Record of Lodoss War for Dreamcast, which was practically a carbon copy of Diablo, which itself was an imitator of Gauntlet. If you've liked any of those games, or Dungeon Siege, you'll love this game.
What I didn't like about Guild Wars was that its level of technicality made it read like a Magic: The Gathering card: "When this skill goes into effect, you lose one enchantment. If this attack hits, you deal +28 damage. If you lose an enchantment in this way, this skill recharges instantly." And with 200+ skills, there were a lot of dispensable ones; Dungeon Runners has a different problem entirely because the three classes pretty much play the same. The game's repetitiveness coupled with its generic classes and the traditional MMO FedEx quests make for a fun, albeit, brainless experience. Still, when the game is free to play, I can't really complain.