aturi, I am also "new" to the .308 AR platform. While I was issued an SR25 as a duty rifle during my service in law enforcement I have never built on until now.
I do have, what I consider, extensive experience with the .308 round, having a background as a USMC trained SWAT Sniper, I mainly used a .308 for over 8 years. I also have, what I consider, extensive experience with the AR-15 rifle, having been a "Patrol Carbine Course" and "Rapid Deployment/School Shootor Responce" Instructor. These courses mainly used the AR15 platform. I was also sent to Colt's Armorers school by my agency to better aid me with teaching these courses.
Having that said, I did some research before starting the current .308 project. I decided to go with DPMS for several reasons, most of which are stated already in this thread. Their lower accepts the 20 round Mag-Pul P-Mags, their prices were the best for the quality of their product and the availability of their parts (excluding the recent lead times) were the best of the current AR10 manufacturers.
The problem, as stated already, is that there has never been a "technical specification package" developed for the AR10 unless you consider the one Stoner did WAY back in the 50's? The military has this for the AR15, that's why their is such a thing as "mil-spec". They never did this for the AR10 as a designated "AR-10" rifle platform, they simply accepted the rifle that KAC designed as the dedicated marksman rifle.
So, having used the KAC SR25, I decided to go with the DPMS LR308 platform. I have saved the money that I could have spent on the SR25 and so far she is a pure tack driver! Although it is still a work in progress I am very happy withthe DPMS I have built. She is keeping up, and waxing the collective rear ends of some of my buddy's who are still active SWAT Snipers using their "bolt" guns.
I have a "bolt" in my safe and wouldn't sell it for the world. This build was something I wanted to do for a fun rifle and one that I was going to build myself. So far, GREAT!