The difference is in the slight details. But it is the details that change the look of everything. Is 60 FPS better? yep. Will it break the game to be 30fps? nope... Somewhere in the forum someone linked a thing that could show you the difference between 30 and 60 fps. It was a cool little link. Perhaps someone could link it. There were actually 2 links... one of them made me dizzy and was awful... The other had 3 things moving and you could adjust each of the 3 things FPS on the screen. It was neat to see.

The human eye won't notice anything over 30fps. 60fps just makes it look slightly better but iv never noticed a difference.