I have shot a few. Nice guns, but had some trouble with them. A buddies car 15 started double feeding, then started going full auto which would eventually end in a stove pipe. He replaced everything he could think of, but the problem persisted. Sent the gun back to DPMS, came back a couple of months later and still had the same problem. Went back, came back, still firing full auto. The gun has a lot of rounds through it, but not enough that it is should be junk, probably a ten year old gun.
Now, I know most people would love to have a full auto AR, but he wants it right. In my opinion, they should replace the gun with a completely new one at this point.