The discovery of a "lemon" in the AR world is extremely rare, although with the rise of the entertrainment industry and 3 Gun Nation the need for reliable firearms, and the exposure of those that are not, has increased substantially.
Many moons ago the list was "ABC" for Armalite, Bushmaster, and Colt. That should give you some clue as to how different BM was seen and how much Colt had slipped. By the time of the first "Chart" it was becoming apparent that the "as good as" brands, simply weren't. For whatever reason Colt had finally gotten their head out of their ass and was making a good gun, and not many other companies were. Couple that with the rise of entertrainment, and suddenly the guy with the DPMS or Oly that the gunshop employee told him was "just as good" was finding out that "no it wasn't". Prior to that most ARs sat on shelves or in safes, got dragged out once a year at best, and when they failed it was chalked up to "Uncle Kenny always did say that they jammed on him in 'Nam."
Today, I think the quality of the broad spectrum of ARs is at least somewhat better. Some credit the original Chart for this. I do not. I think that consumers are simply becoming more savvy, and more interested in having guns that actually work. Now, that said, more savvy often simply means that they know enough to be dangerous. Customers start to learn a little bit, demand that their carrier key be "properly staked", and the manufacturers start staking them. That does't mean the carrier key material is correct, or that the bolt material is correct, or that any of them have gone through the proper testing and QA/QC process, etc. it just means somebody took a chisel to your carrier key.
But, the key is probably better off staked than not staked, and the receiver extension is probably better of being "milspec" diameter than "commercial", and whatever other superficial changes the also-rans make.
To date, I haven't found anyone that does everything the way Colt does (or, the way the spec says they should), and even Colt misses some steps (un-staked keys are becoming an increasing occurrence). But event he bottom-of-the-barrel have been dragged up, and even when the middle-of-the-barrel gets something wrong it doesn't really matter that much.
And then you have all these people with their "improved" extractors, carriers, coatings, etc. It's a confusing time, but it probably doesn't matter.
