Tonymacx86,
Thank you for posting this because this situation has been one of great frustration. I have never downgraded from an update in all my Mac days. I've always looked forward to each new update with anticipation and really dug in to all the new features but 10.9 has been the most disappointing that I can remember. I actually had to go buy a 2nd ssd just to be able to continue working (one for 10.9 experimentation and one for 10.8.5 work, which is very stable).
I sure hope that the AMD HD7970 get sorted in 10.9.x otherwise I will be stuck at 10.8.5 for a very long time. I'm posting benchmark shots from each OSX. The performance hit is very noticeable in many apps. 10.9 has some really nice and much need features dealing with multiple monitors as well as tabbed finder windows that I'm already missing going back to 10.8.5.
Thank you for all you do for this community!