Firefox 4 beta is very noticeably faster than Chrome on my Mac in heavy JavaScript/Canvas experiments. Chrome is especially a dog when in fullscreen (2-3 times slower) for some reason.
Unfortunately, this seems like another example of FireFox optimizing for the wrong thing.
To the casual user, FireFox seems "slow" because it takes 30 seconds to start up when you click its icon. Chrome takes under 5 seconds, and is thus "fast".
Nobody but you and me care about how fast our javascript runs. The FF team is trying to please us, while ignoring the 99% of users who'd prefer to just be able to check their Facebook in the morning without waiting forever.
