I'm new to the AR game (as in "babe in the woods" brand new). I purchased a bare lower receiver (Rock River) last November. Just got around to buying a parts kit for it last week (made by DPMS). Instructions on line made the job fairly simple, and all springs, pins etc. went into place perfectly. After installing the parts kit, I picked up a Rock River bare (flat top) upper receiver and a Rock River collapsable butt. The Rock River marked parts look like very high quality to me, but I also notice the "key hole" emblem on the receiver parts, which, I think, indicates the major provider who makes parts for several of the AR players (who then etch their brand on the parts). All of which, I suppose, goes to support Lloyd's observation that there isn't much difference between the bare receiver parts.
I ordered a 16", stainless, match-grade, bull barrel with a "Wylde" (I think that's spelled right) chamber in early December. My friend tells me the barrel is due in this week or next. Ain't easy gett'n parts in this environment.
I don't think I've saved any money building the gun from parts, but I've gotten a lot of satisfaction from doing the work myself AND I have a much better understanding of how the gun works. I've also been able to build the gun I really wanted, and, I guess that's worth something.
My Sportman's Club uses military rifles for a steel shoot out to 100 yards during the Summer. I'm planning to use this carbine for that purpose. I'll also find some comfort having a capable sport utility rifle in the safe in the undesired event of civil unrest. Even so, I probably wouldn't have invested the $ to build the rifle if I didn't believe the current administration is likely to take this right away from us.
PC