Earlier quoted context omitted.
What about testing on Windows?
With the exception of fonts there should be virtually 0 rendering differences between osx and windows versions of the same browser.
Re: Cross-Browser Testing Tool Will Rock Your Socks Off
#31I've run into the situation more times than I can count where there was some little display difference between, for example, FF on OSX and FF on Windows. Always pays to spend the short amount of extra time needed to test across operating systems.