Unsure about IE9, I have IE8 at work and it is incredibly slow at downloading a page from this site, far far worse than any other site I visit. (IIRC the home PC wasn't being a lot speedier although I can't recall what that is, IE9 I'd guess.)
That said Firefox at work just brings up a zoomed out view. Too small to read. Unsure if that is a website issue or to do with Firefox apparently not being able to update plug-ins, for whatever reason.