I got my copy at 9:30a CST, upgraded my MBP went fine.
Then moved to my Mac Pro, UPGRADE it also. Sata came right up, Kona3 with a 720P project played out just fine. 1080i multicam project played a-ok.
I know this is light testing but off to a good start.
BTW: Both systems were cloned before doing this. Also all external drives are disconnected when I do an upgrade.
Time Machine is a slow copier, looks like about a GB per 3 minutes. I have set an Internal 500GB drive up for Time Machine for the Mac Pro.
Stuff like Mail and Safari is super fast on my MBP.
Two systems upgraded in about 3 hours!