There seems to be something really slow about javascript-heavy sites on Unix, I think.

I'm really curious what the underlying cause is, if it's not just perception bias on my part.

Possibly, since I don't use anything else I don't know (except in a virtual machine). I get the impression however that the firefox people spend a lot of time optimizing for MacOS and Windows that they don't spend on Linux for some reason.

same for IE6

Performance is not a problem in Chrome, but readability is. It's virtually unreadable because of fuzzy text rendering.