Adept here, I like to be the immovable camping wall. Actually class could matter less in multiplayer. I have my M5 Phalanx. The most imbalanced gun in existence. I've heard rumors of even better ones.

I see more people using the Carnifex than the Phalanx, actually. I haven't unlocked that one yet though. And apparently there's an http://masseffect.wikia.com/wiki/M-77_Paladin of the Carnifex. The Phalanx is amazing though, even better than it was in ME2. Especially with a scope; miniature sniper rifle, anyone?

That's racist!

http://www.gamesas.com/topic/1355032-mass-effect-thread-56/