Just dropping a note to say that the MSI Z77MA-G45 motherboard with UEFI works perfectly under Arch. Initial installation was a little bit painful because I was installing from a USB drive that was not booted in UEFI mode. By following this guide and the installation guide, I managed to install refind, which got me into Arch, then I just repeated the GRUB2 installation steps to complete my install.
Systemd is a little weird and will definitely take some time to get used to, but I really like the new 100% manual installation method, along with the improved Arch bootstrapping and chroot'ing scripts. Very happy to see that this is still the same (but better!) distro that I used 6 years ago.