I normally play shooters on the PC. The PS3 version includes keyboard and mouse support. PC elitist are going to be in for a rude awakening when they realize that some of their PS3 opponents will play just as good as PC players because they may be PC users as well. EDIT: Now that I think about it... all of my friends that own consoles are PC shooter fans and they aren't push overs.
Maybe. I'm sure there will be some. I don't actually play shooters much myself (I play Counter-Strike and that's about it), but I do have a couple friends who get really into that professional PC gaming stuff. I've never been able to do it, but I have never seen either of them lose a random online match... ever, unless they are playing against each other. Professional shooter gamers are like WoW addicts. It becomes their life and they just rip through those who play them casually.