I've been using Firefox for years (Screw you, Internet Exploder), and jref has never (directly) caused a crash for me. I usually access this site via Windows XP via Boot Camp on a MacBook, or via fedora Linux.
It could depend on your OS. The OSX port of Firefox is disgustingly inefficient when it comes to the amount of memory it uses (same could be said with just about any third-party software for OSX).