I built a 6.8 with White Oak parts. It's been reliable and accurate, but I can't speak to its lethality yet as the deer seem to avoid me when I have it with me.
Kotonics went out of business a while ago. They had a problem where the chrome lining in some of their barrels was too thick and was causing overpressure. They did their best to fix it, but went bankrupt trying to make things right.
$825 isn't a bad price. If you get it and find pressure signs, worst case scenario you could rebarrel it with something from this guy and be good to go.
http://www.ar15performance.com/6_8_arp