Well, Im not being biased but a keyboard and mouse will always be superior to any of the current console controllers when it comes to an fps game.
Controller Simply cannot match the precision that k&m can in shooters.
Only area that consoles controllers trump a k&m is in fighting/racing games. The k&m is too complicated and large to play games like that because they don't rely on the mouse but rather on the keys in which case the k&m has too many.
Try playing DiRT on a keyboard, and you find it is almost impossible!