Hi Jasper,
We've been running Flex on JRun/OS X for a while - I first installed it on OS X when I was at Macromedia shortly after the 1.0 release. The only thing we've noticed is that the fonts look much better running our apps in Firefox than Safari - and that the font widths are a bit different to Windows, causing some layout issues when windows users viewed our apps in IE.
Robin http://www.rocketboots.com.au
