I have audio working, thanks to Mirone. As far as I know, everything on the board is working 100%, including sleep and power management functions. This board is actually very compatible with 10.8.5. I'm working on an installation guide that I will be posting soon.
Hope to see a guide soon!
Would love to get OS X working on my Maximus VI impact....
I had thought about gigabyte again, but i had some problems recently with a GA-Z77N-Wifi that shorted out and sparked then caught a test bench on fire... one of the standoff sections on the board had a small fracture in the PCB board and it crapped out on me.. almost took my video card and new corsair dominator platinum ram with it... I took the board in to be RMAd by the stoer it was purchased from there was a 5 socket pins that were slightly bent or misaligned and I was told
" due to physical damage to the motherboard we are unable to RMA the motherboard blah blah blah..."
I swear the socket pins were fine when I brought the board in for service now I don't want to support them hence why i am leaning towards ASUS