Asides from the occasional turn-based gem, great multiplayer mobile games are few and far between on the App Store. Assassin's Creed Rearmed is easily one of the best we've seen. It's totally unique, and a great mobile extension of an already stellar franchise.
Assassin's Creed Rearmed comes with a fast matchmaking system and lots of things to unlock, most of which you have to pay for. The controls don't work good as they should, however, making the whole experience very cumbersome and annoying.