I don't usually upgrade to a new OS version until X.3 or 4 so the bugs are cleared. However, for those using Premiere Pro CS6, upgrading to Mountain Lion OSX.8 will give you a boost in performance and stability. Open CL acceleration is better, real time playback is faster. Just about everything is better and more stable. I was given this tip by Adobe themselves and finally bit the bullet. It works better. I was crazy enough to even do it without my Adobe Master install discs with me.
However there are a few caveats for those using AVCHD cameras:
http://blogs.adobe.c...ntain-lion.html
For other formats, it's working fine and peppier! I'm not digging a few new features with OSX.8 but it is very impressive as an OS. Makes me wonder why I paid for OSX.7 and why they didn't name it Lion instead of OSX.7 (a sham OS upgrade if there was one!).