UEFI, does it offer an advantage for a Win 8 PC?

Well, I'm way in over my head on the subject, but just for starters, I can imagine a bit how that works. The first sentence:

"The UEFI 2.2 specification adds a protocol known as Secure boot, which can secure the boot process by preventing the loading of drivers or OS loaders that are not signed with an acceptable digital signature".

​Some "malware" comes along, and replaces the original driver or OS module with it's own version. From then on, every time you boot up your PC, the virus is getting loaded, because it's now part of the OS.

​But with UEFI 2.0, right from the start, UEFI sees that something isn't right, because after the malware has replaced the driver or module, the "digital signature" is no longer the same for the driver or OS module.

In the "rootkit" Wikpage:

http://en.wikipedia.org/wiki/Rootkit

they say:

"Rootkit detection is difficult because a rootkit may be able to subvert the software that is intended to find it".

And then they mention "signature scanning", among several other solutions.