I've only bought one complete AR, a Rock River. I've also only put together 12 (yes I said put together, because I buy the barrel assembled, meaning extension on and headspaced, which I do check). I just like the fact that I can put whatever together any configuration I want without having to have left over unwanted parts, (because that usually leads to another build). I spend a little more, but like I said, I get what I want. I've only had one AR that had any problems, and that was from an out of spec lower. Every one of them shot moa or better and functioned great. Of course I don't really push to the edge of durability because I don't need to.