Seriously anyone that says they can't see the difference between 30fps and 60fps must have something wrong with their eyes. It's like night and day, particularly when you turn your guy in a fps.
What I will say however is that 60fps sometimes doesn't look good in cut scenes, I played Mass Effect 3 at 60fps on a PC and the cut scenes completely lost their cinematic feel to them running at 60fps, just made it look far to artificial.
Gaz9000's comments