The last time I checked, Colt was the one that did not have receiver or barrel materials posted on their website.
Also, I have put better than 10,000 rounds through my dpms upper, and have had no issues with it. Does it hold sub moa with wolf ammo? Hell no. Does it do so with my handloads? You betcha. That rifle and myself have won 3 gun matches against guns that cost easily twice as much.
The information is out there. Colt uses "Mil-Spec" in the correct sense. As in adheres to the TDP. Other manufacturers (not all) erroneously use the term. They may meet material requirements but they fail to meet the inspection/quality control requirements.
If you shoot 3 gun, you've seen guns have failures. More often than not it's repeat brands you've seen before. You also know 10k rounds isn't a big milestone.
I don't doubt that you out run rifles that are two times or even three times the cost. It's the guy pulling the trigger who wins, not the gear. But, your gear can stop you from winning.
I shoot with guys who pull first place finishes with DPMS's. I also shoot with guys who pull last place finishes because their DPMS wouldn't run.
You, as well as I, know a few hundred bucks between a gun that may or may not run versus one that will should be a no brainer.
The firearm itself is the cheapest and most critical part to shooting. Ammunition alone will easily be twenty times the cost over the lifetime of the firearm. Why not set the OP straight now when he's making the Step 1 decision?