In the case of Firefox, this question has little meaning. Firefox is an XUL-based frontend on top of a small runtime interpreter. The frontend is largely the same across MacOS X, Windows, and Linux.
Slightly OT, but I've never had a crash with chrome, I have with firefox. And camino seems to be lacking a few usability features which you won't notice up front, but will irk you if you like to get the most out of your browser's features.