Not sure if this is one for you or one to throw at the firefox beta team but the text in v4 looks bad. Particularly the crumb trail. It's something to do with the anti-aliasing firefox is using. It's find on scratchlive.net and whitelabel.net.
I'm using 1280x1024 on Windows 7, the problem doesn't seem to be related to the size of text as it persists when I zoom the page.

Hm. Yep. Looking at it in Firefox 4 beta 3 here and I agree, a lot of the fonts are being rendered badly.

Best to wait it out until Firefox 4 hits final. If it's still a problem then then we could use a different font for when viewed in Firefox perhaps.

Do you have the latest beta nobspangle? It's looking good for us now.

it looks much better, to be honest most sites look quite bad in firefox 4 now that they're using the D2D rendering. I'm slowly getting used to it.