We are running OSX in our design studio, and finally recently updated to Acrobat 6.0 Pro. Unfortunately the 'Print to Acrobat PDF] plug-in is rather fiddly to set up, requiring skills far beyond the average Mac OSX user (terminal session work etc). I'm still working on it, and I'm more experienced than most in the design profession with Mac OSX.
If you are going to move to OSX, definitely move to the all OSX Acrobat 6.0, as font activation between OSX and OS9 is not good with Acrobat 5.0 (which still has Distiller running in classic, which is the problem) and the various OSX type managers available (Distiller 5.0 lacks the ability to invoke font activation).
If at all possible, it is worth moving COMPLETELY to OSX, upgrading or replacing all OS9 apps with OSX versions or equivalents (InDesign is a much cheaper, and VASTLY superior alternative to Quark in my experience). You'll find it much smoother with just one OS (We had to have classic around for running distiller 5.0, and there were often issues with fonts).