Generally the gameplay is fine for me. Some big games get a bit laggy, but it's no different than playing on a PC for me.
As far as the cheating goes, at least when I last checked (3 or 4 weeks ago), it was possible to cheat in R6 using Action Replay and gain access to weapons you weren't supposed to be able to use. The only one I knew of particularly was the molotov cocktails, and those tend to give you away instantly... a flaming comet released from your hand will do that.