Firefox was taking its toll on my 7 years old Atom-powered netbook, especially the sync feature, which is so useful but so damn resource-sucking. So I switched to Qupzilla which is doing a decent so far and it's quite lighter and faster. However, it crashes often when I play on Showdown =(
Firefox is still my browser of choice on my main PC, though.
I use to use only Internet Explorer, but when I found out I couldn't make posts on Smogon with it, I switched to Chrome since it was the easiest to access and I legit thought Firefox was only for school computers.