FaceTime for Mac is out of beta as of today. Honestly, I didn't think it would leave beta until Mac OS X Lion's release this summer. The big new feature is HD video calling if you have a FaceTime HD camera (currently exclusive to the MacBook Pro line that was refreshed today).
FaceTime for Mac comes with the new MacBook Pro, or is available for 99¢ on the Mac App Store for the rest of us.
Some folks I've spoken with that had the beta installed say they are sticking with that. Your mileage may vary. Me? It's a buck, and I use it quite a bit.