On my Mac I use Firefox as it is the quickest for my purposes. I go to Safari now and then and it works fine. It seems to be getting better.
I use FireFox, to read FreeRepublic, because it lets me choose the display fonts. I need a heavy font to help me with my impaired vision. I use Safari for most other browsing, would still use it if they allowed me to change the fonts.
ps I use Casual Bold 28 point for FreeRepublic, rest of family hates it but I can actually read it comfortably, on the big screen TV I use for a monitor.