Vanguard is the only answer here, and anyone who claims otherwise is a liar.

anybody who doesn't say infiltrator, hasn't played with the infiltrator yet.  Slow down effect FTW!

Vanguard gets the slowdown effect after using Heavy Charge.

Charging is pretty much the whole reason that Vanguard is the most fun.

I played as a soldier :( didn't know vangard was so aweesome, still those concussive shot saved my life more then once on hardcore

Vanguard all the way!

i went with the one with the sniper (forgot which one is that)

Soldier class, biznatch!  Sure it's a bit vanilla, but the sheer multitude of tools at your dispersal means you can approach any situation in one of about a half-dozen manners.*

*I don't recommend sniping with the shotgun.  But you can!

Vanguard is the complete warrior. :)

infiltrator gets it just for aiming, so.... it wins.  and they can turn invisible and sneak up and stab in the back, super cool and fun.

Soldier is for punk-ass newbsprites who can't work their way around a Y button!

Yeah I'm talking to you, newbsprite! Gonna go play some more easy mode with your easy class, newbsprite?