I have a UEFI secure boot MSI laptop with OEM Windows 8 installed. I heard about Linux Mint, tried the DVD ISO version and it looked good. I had difficulty booting into Linux at first until I switched to Legacy boot mode. Then all was well. I played with Linux Mint for a bit. Of course, the settings changes I made were lost on reboot. So I took the plunge and installed as a dual boot system. I used the quick and easy partitioning rather than manually configuring. All seemed well. I had to reboot and manually switch from Legacy back to UEFI boot in order to get windows to work and back again for linux. It worked for a couple of days. Then one day Windows detected a "corruption" and tried to repair itself. Further research told me that the new security bios does not like alternate boots; this is in order to protect form Root kits.
My Windows became unstable and eventually got stuck displaying "Preparing automatic repair". I thought all was lost. I took it back to the store to have them reinstall windows 8. I was floored when they said that installing Linux voided my warrantee and that if my restore partition was corrupted, they would have to charge for a new windows operating system as well! Fortunately, I somehow got windows unstuck, the recovery partition was still valid and I had my data backed up (Windows partition was readable within Linux Mint, which was still operational). I reinstalled windows, blowing linux mint away.
Sooo... In answer to your question, UEFI does NOT work directly with Linux Mint. GRUB 2 seems to work in legacy mode but Windows 8 is badly behaved and does not play nice. The sulky brat tries to "Fix" things and messes things up.
My advice, don't install dual boot with Windows 8. Oh, and make a DVD backup of your Windows 8 just in case so you have protection against corruption.
Update: I have discovered a conflict that may be causing my "Preparing Automatic Repair" problems. I have an old laptop drive I mount externally to my computer using USB 3 (NexStar3). The drive used to be bootable, but I erased much of windows and the recovery partition. The USB device is set in the boot loader priority before the Laptop hard drive.
If I simply unplug the USB drive, I do not get the Pre Auto Repair screen.
As an aside, perhaps if I install linux on THAT drive, I could have my dual boot. Then I would not be using GRUB 2 at all.