FF3.6 is (obviously) by far outperformed by Chrome, but it seems to me that even 3.5x did a better job of running it. In either case, the 3.5->3.6 difference seems marginal for this one.
This isn't the only site that Chrome is slower on. There was a link on Reddit or HN a while ago about an image blurrer that was entirely written in JavaScript. FF 3.5 managed to be 2-3 times faster than Chrome for that particular page.
Chrome is faster than FF 3.6 on some sites, like Mockingbird, but it does not always outperform FF.
Did you ever measure the difference with the Windows versions of the browsers, on said web sites?
In any case, FF 3.6 definitely doesn't feel slow on that site. Everything is pretty smooth except for scrolling which is a little jerky. http://www.youtube.com/watch?v=lQ2PDbffKuQ
All in all FF 3.6 is a very nice update. It's noticeably faster than 3.5 on many websites. I used to use Firefox for general browsing and keep Chrome around for a few select websites that Firefox was slow at, but with this update FF is sufficiently fast so I don't need Chrome anymore.
On Windows/Linux though, chrome is the fastest you can get.
I'm amazed it even renders, though. Kudos to the old Android browser for that!