I have a 6.8spc 20" ARP target crown barrel in a mildly built AR15. I do a yearly hunt in Texas and the last 2 years have been doing strictly management on a hi-fence property. I've shot around 25 deer using 110gr Sierra ProHunters, 110gr Barnes TSX, 90gr Gold Dots, and the Hornady 120SST which beats them all.
West Texas white-tails are not that big, so 120-150lbs is about average. Most shots are in the 150yd range, but a few out to 300yds. Every deer I've ever shot, regardless of bullet, has resulted in a complete passthrough with good blood, and a 20-30yd average run. I'm strictly a lung/heart guy, so I expect that they won't be DRT, and the dog loves to go "find" them even though they're usually laying in sight of the feeder.
The 120SST's and Barnes shoot 1MOA, everything else I've tried is in the 1.25"-1.5" range, except Remington FMJ's that were complete crap.
The caliber has done everything I've ever asked it to do and I've never been disappointed. I chose it for strictly ego reasons... the Grendel was too damned snobbish, the 300blk was too damned fat, the various wildcats were too damned expensive... the 6.8spc just seemed like it had everything going for it and nothing to dislike unless you'd already bought something else and were going to crap on it just because.