Just a word of warning.. Once you go UEFI you can't go back to F10/F09/etc.... Or at least I haven't found a way. So, if your system is working okay you might want to hold off on the update as some people are reporting problems.
I was able to get everything working except HD3000 on 10.6.8. Which I hoped to stay on... However, after spending a few days with no luck I bit the bullet and bought 10.8. It's downloading now so hopefully I'll have it resolved by tomorrow.
OK. I have my optical drive working, for some reason it only works when attached to one of the white SATA ports, connected to a blue port and it doesn't work. The eject button is also working fine.
I installed UEFI then the system would not boot. Kernel Panic. Keep in mind that this is for an upgrade from Lion. I then installed ML on a second disk I had and it worked fine (even Airplay to Apple TV). In the end, I found a way to boot the older HD: I use DSDT=/dev/null as a boot argument and used Multibeast to force the options as per your suggestion. The only thing NOT working on the old drive are Airplay and USB3.
So, if someone is having problems with an upgrade, try a new install, or use DSDT=/dev/null.
Question: I can I remove the old DSDT effects and reset Multibeast settings once and for all? (I have to type DSDT=/dev/null at every boot...)