I just installed Loki on my desktop, ASUS Z87-PRO, BIOS:2103 32GB DDR3 (1866MHz) i7-4790K R9 380 (primary) GTX 970 (secondary)
I have tried installing from USB and DVD, straight install and from the liveCD mode. It seems as though Grub is not installed by the installer. At boot all I getting is a flashing terminal courser.
On my laptop the install works fine just not my desktop.
Following on I remembered I had downloaded the beta early last month and decided to try installing that. For some reason the beta works but the stable version does not. I guess I just have to hope that updating the beta brings me up to the stable