I have a dual quad core MacPro running OSX. I am a videographer and use PrPro for editing. After I open a project I'm working on, I can start the playback and then the cursor freezes and even though the sound continues I cannot get the app to respond, thus I force quit. It has happend three times in a row. I regret "upgrading" to OSX but I'm not willing to go through what it takes to uninstall and go back to Snow Leopard. All I want to do is do my work and not have to deal with this.
If you have been usingTime Machine, it's relatively easy to rewind your system back to Snow Leopard.
Keep in mind that Lion has been out for all of three weeks. And the first release of any new OS is really little more than a glorified beta. While it's adventuresome to jump right in to the new and innovative, being on the cutting edge often cuts you back.
Adobe engineers would have to speak to this, but I'd imagine every major OS release (for any platform) has big changes to the underpinnings of the system.
This is one reason Avid takes months and months to certify an OS before approving its use with its systems.
Personally, I'm waiting for 10.7.3 or a Lion specific CS5.5 update from Adobe before making the leap.
I'll get off my soapbox, now.