With a quality GPU, Vsync won't have the typical downsides of delayed response. It's all in the hardware. Quality in, Quality out is the golden rule.Nope.
yes you can only see 60 of those frames per second but the image looks at lot smoother and consistent at 120fps even if you dont' have a 120hz monitor.
If i get below 90fps in a game it feels horrible. I like being able to do a 180 turn in game with the game looking as smooth as possible.
edit: of course my personal perception