For quite a while any WebKit based browser (Chrome, Safari, but specifically Chrome) seemed to have a huge performance advantage over anything else I tried. Nothing could touch Chrome for Javascript performance. Now I'm developing some fairly Javascript heavy stuff (webapps) for mtvan and I'm finding (on a Mac) that Firefox definitely has the lead over Chrome. Not long ago Firefox seemed to be a bit of a bloated pig that crashed too regularly.
This might not be the case on Windows. For anyone that takes an interest in this stuff, how do you find they compare?