Just performed a clean install of 8 to my ASUS laptop that was 8 from factory that I downgraded to 7, used 7 for almost 18 months, and then removed 7 and brought back to factory 8 in prep for 10 vs blowing my Windows 7 key for the 10 free upgrade. Fortunately the 16GB thumb drive that I placed the recovery to before the downgrade to 7 worked.
Only problem I had which I am unsure if its still a problem or not is that when it got to the Windows 8 key activation, the laptop doesn't have a key on it other than one that I have been told is hidden in the BIOS. So where there is a field to normally enter a windows key, I have no information to enter wince the laptop has a Windows 8 sticker on the bottom of it, but no alpha-numeric key to enter. Fortunately this key window had a SKIP option, and so I did this and then when it got connected to the internet, I am hoping the embedded 8 key was read from the BIOS and its now satisfied. I took a few minutes looking around to see if Windows 8 needed to be activated and it didn't seem to show any indication that it needs to be activated to X-many days etc, so hopefully it will continue to work and not timeout.
UEFI was disabled on the BIOS for the Windows 7 install and installing 8 back to it, I am not sure if UEFI was reconfigured as active again from the 8 install or not. I suppose I will have to check on this as for the initial factory build had the BIOS access locked out from Delete key or any other key to try to get into the BIOS at boot, and I had to go through an extensive process to force Windows 8 to tare its claws out of the grasp of the BIOS to re-enable the BIOS hot key at POST to actually function. The initial build had where you had to ask Windows 8 to have access to the BIOS to get into the BIOS. This was one of my pet peves with Microsoft and Windows 8 to restrict BIOS access at the POST level. Which to me was intentionally done to try to anchor the Windows 8 to the hardware and make it hard for people to get rid of it as for I dont see any other strategic reason for Microsoft to target to hold hostage the BIOS access at the POST level and then hide the ease of access to gain access to the BIOS for users in which you have to request 8 to grant access to the BIOS, and then it would reboot and then allow access to the BIOS.