The only bad thing about firefox is that ebay's servers aren't well supported for them. At least that's been my experience. For instance on the old sell form (why oh WHY they had to switch to the new form!) you can't put in a standard listing with html integrated. You can put in html, but that takes time. I suppose you could save a template and then change just a few things, but you'd have to start from square one if you ever ran into ebay problems. Another thing is the ebay chat seems to be less cooperative with firefox. These are all small prices to pay for having firefox, but still ebay should get with the times.
On a related note, does anyone know if download history can get you into trouble just as easily as the cookies and cache? I have firefox set to delete everything but the history upon closing. I keep about the last 10 days in reserve just in case, it's nice to be able to revisit old search pages and whatnot sometimes, especially if you're not logging into suspended accounts, just looking at pages you visited on good accounts. Plus I'll admit I'm a bit of a packrat, I like to think of it as being prepared

I wonder if that is the major cause for a system slowdown. I have been having problems with that lately. Maybe I need to cut it down to just 5 days...