I use Chrome, primarily. I dunno what it is for everyone else, but I've never had problems with Chrome. It's always worked perfectly for me. The only other browser I use is FireFox. And I only use it for GameTap, as the new browser based system doesn't work well with Chrome.
(BTW, I'd be happy to trade one of my premium sub-accounts for a BFH key,
. I couldn't do it right away, but only because they've recently disabled them to implement it into the new system)