I was actually surprised, the multiplayer got a hell of a lot more play from me than the single player campaign (pretty much guaranteed, really) and a lot more than I was expecting even then. It's a genuinely interesting concept and it greatly refines the gameplay from the first K&L. Only problem is, well, you pretty much get what you'd expect. It seems that the whole "betrayal is the game" aspect is lost on most players. If you betray them, prepare to be called everything there is. If they betray you, be prepared to be called every form of stupid for not betraying them first.
There is some legitimate fun, just turn your mic off.