With the Rev 1.0 board, I've had all the symptoms everyone else on this thread has had -- sometimes sound would come and go while I was working on a document or browsing; sometimes it would boot fine, other times I'd get the white window and frozen cursor; sometimes boot to snow crash screen; no USB 3 ports working at all. I use the ALC887 current for audio and the Atheros something 123 for network.
So I used Unibeast 5.0.1 and Multibeast 7.0.0 and reinstalled Yosemite, following Tony's guide. I use the DSDT-free process. I initially put in the GenericUSB kext, but that didn't work. So I booted from my Mavericks drive and removed that kext from the Yosemite drive and rebooted. Now, USB 3 ports are good. Tony's advice to make sure that BIOS settings for XHCI mode be AUTO, and that both XHCI and EHCI handoff boxes be ENABLED are important.
My craziness seemed to start after I downloaded and installed the new Nvidia Yosemite drivers. The reinstall took me back to the Apple default drivers, and I think that helped. But the looniness of this whole experience has me spooked. Mavericks went in without a hitch, so I was thinking this might be easy...
The only problem I have now is losing audio after waking from sleep. I hope toleda or someone will get that fixed. I can't figure out how to correctly use CodecCommander, which toleda linked to on his troubleshooting page -- I'm not a terminal whiz.
UPDATE Oct. 24 -- Audio now seems to be working correctly -- I used the ALC887 current kext and Patched AppleHDAEnabler with Multibeast 6.1, which is what worked in Mavericks.
UPDATE Oct. 25, 2014 -- After using the older kext, patched AppleHDA, and HDAEnabler, USB 3 ports all dead, with sound gone on waking from sleep. Reinstalled Yosemite, made inplace-patch recommended by toleda -- see Audio - Realtek ALCxxx page on this site. Sound now working, with recovery from sleep AOK. USB 3 ports still dead. Tried GenericUSB3 kext from MB 70.1 -- doesn't work, removed.