This board rocks, I highly recommend it. I built a workstation for HPC using this board:
2x EVGA nVidia Titan
2x 32GB 64GB Corsair Vengeance CMZ32GX3M4X1866C10 1866Mhz but clocked at 1600Mhz (maximal official supported speed)
2x Cooler Master 412S
1x Kingston 480gb hyperx 3k SSD
I currently use Ubuntu and it really works flawlessly. I just bumped into some minor annoyances e.g. if you try to force the RAM speeds higher than 1600Mhz it may not post anymore, so you need to clear the CMOS and to do that you need to move a jumper that is hidden well below the graphic cards ... not very practical. For this price tag they could have simply thrown in a CMOS reset button like the RIVE has.
All in all, I am really happy with the functionality and performance. The BIOS comes with tons of settings and seems possible to overclock, though I haven't done so except changing the RAM speed.
If you'd like to see some HPC benchmarks, this is a project I have been developing with it:
UPDATE: The following is a performance guide for this motherboard which I try to keep up to date (updates, suggestions welcome!):