I used to use Firefox, but was having constant problems with scripts running that I couldn't see until a notice would finally pop up giving me the choice of stopping the script or letting it run. I never knew which scripts they were. Even though I liked some of the add-ons, I don't use FF much anymore on the Apple side of my MAC. I still use it on the Windows 7 which I run on VMWare Fusion. I've about given up on IE. It shuts down almost as soon as I open it.
On my MAC operating system, I have found Chrome easier to use and more stable that Safari. I occasionally use Safari if Chrome does decide to act up. I also like the way Chrome makes it easier to access all my Google sites. I use Docs, Analytics, Google+ and YouTube.