I recommend the use of Google Chrome on OSX, since Firefox really seems to lag in terms of features there (the upcoming Firefox 18 will be the first with Retina support).I have no problem with people using Chrome (I, myself do) but saying that Firefox is behind when it comes to features is kind of a lie.
Look at some posts from the mozdev blog[0] and see if you don't find three or four features that you don't see in Chrome but you would to!
[0] https://hacks.mozilla.org/articles/
