I haven't been here for some time been over at the 6.8 forums.
I don't know if you have decided on anything yet but you might want to consider building your own, they are very easy basically Legos for grownups. To build one you will need some basic mechanical inclination and about 100-150 bucks in tools, mainly for the upper assembly. Or you could buy a complete upper assembly and build your own lower about 30 bucks in tools. There are quite a few shops building high quality uppers with very reasonable price tags and all are Mil-Spec.
My first build took me 5 hours mainly because I kept taking it apart and re-assembling it. I was sure I was doing something wrong because it was so easy. I have since built 5 more and am now taking around 45 min from a box of parts to an assembled rifle with optics mounted and bore sighted. Not blowing my own horn just saying it is pretty easy. By the way all the my rifles are capable of sub MOA and are absolutely reliable. You'll want an assembly manual or a DVD which ever format you prefer. I use the "Complete AR-15 Assembly Guide" by Walt Kuleck with Clint McKee.
Below is a list of suppliers I have used most of them also offer complete uppers and rifles and all are exceptionally quality.
YHM, Yankee Hill Machine Co., Inc. | Makers of High Quality Firearms, Accessories & Sound Suppressors
Rainier Arms™ | Specialist in High End AR15s/M16s,Stocks,Grips,Parts,Accessories & much more
Ammunition, Magazines, Rifle Parts, Bulk Ammo and Rifle Accessories - Palmetto State Armory
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Del ton Rifle Kits & Del ton AR 15 Rifles | Gun Supplies & Gun Accessories from Del-ton, Inc.
Innovative Tactical Systems LLC, Made in USA, AR 15 uppers, piston operated tactical upper, 5.56, 6.8spc, custom precision barrels This guy is great
AR-15 Parts Including Complete Uppers, Lowers, Lower Parts Kits, Triggers, Magazines, and much more!
Spikes Tactical
There are a lot more but I would start with these. I would stay away from DPMS rifles unless you are willing to spend the money to replace most of the internal parts.
Here is a pic of my first build. If you need any more info PM me I'll be glad to help.