I'm a developer at Mozilla, so I wanted to test your site so I could file an SVG performance bug for Firefox. :)
I see that Firefox 13 is significantly slower than Chrome and Safari, but Firefox 16's Nightly builds are much faster. (Firefox Beta 14 and Aurora 15 are just as slow as 13.)
To my untrained eye, your demo is "only" about 1.5x slower on Firefox Nightly than Chrome and Safari. Is there a way to quantify the speed difference, such as FPS or time to completion? The demo ends at datetime 2012-05-22T00:48:10.