I can't wait for you to try with ML. I was planning on ordering the GA-Z77X-UP5 TH but i am waiting to see if the thunderbolt ports work... For the audio i am not too worried, i got pretty good at manually coding VoodooHDA to make pretty much all the cards work. Ethernet i couldn't care less since i bought a PCI Ethernet Card that works OBB (Kitty & Mountain Kitty). Since it is a UEFI board, will it need PowerManagementNull kext?
And of course, the famous USB 3.0 ports. Which i wouldn't mind buying an external card for but we have to see what's compatible or if there's a way to make them all work. So it's a pretty risky board for now until we know what's working and not. Not mentioning the whole DSDT that has to be written... But still, i ordered my Mac Pro case
Waiting for more results on Mountain Kitty!!
EDIT: Almost forgot, thank you for reporting all of this
Very appreciated. What can i say, i love people who helps me make better money-related decisions