Recent version of all browsers have roughly the same performance. But you need relatively new hardware. Old p4 and on-board graphics card won't handle it.
I'm on a six month old maxed out Thinkpad W520. I don't think they have much in the way of newer hardware than that, so I suspect it's more likely that there's a "smooth scrolling" setting somewhere that one could presumably turn on to see this effect.
Somebody else mentioned that it's on by default on Macs, thus confirming my theory about the "web-designer-only" build of Chrome (the same one that renders those extra blurry fonts that designers like to use on their blogs correctly). Chances are nobody with a Windows box ever saw this in action before they pushed it live.
I'm using the latest Firefox on windows 7 and don't seem to have a problem with it.
Mind you it's a desktop and I'm using a mouse not a touch-pad to scroll.
The slight choppiness i see is because of how scroll works not the website's fault.
When you scroll there's a minimum increment that gets detected and the equivalent on the website for that is quite large.
But reducing that would make you scroll a lot more and would probably be annoying.
If you want the smoothness of a magic mouse use the down arrow on the scroll bar or your keyboard.
Smooth is one part of the problem, the other is getting stuck between two "frames" after scrolling: http://imgur.com/gtJGtsT.png
Scrolling gives you no visual feedback for "content units" like margins around paragraphs or headers. You cannot be sure if a "frame" has all its animation loaded until you scroll down - up - down a little bit. Imho that's not a pleasant experience.
