Should I purchase a Porter Cable; I've heard nothing but good on these polishers; but it seems they are recommended to beginers; I've used nothing but a rotary for so long (which I'm very good at) but maybe this PC can bring my last step to a new level.
if you know your rotary I wouldn't bother with the PC. Its a great tool for beginners and they are developing processes to make it faster and more effective but it still dosen't come close to comparing to a rotary and the knowledge of how to use it.
What do you feel that you are lacking? If nothing then you have nothing to worry about. If you feel that you can so what you need to do with a rotary, then you might not be missing anything.