Personally?(Just stirring it up in The Pasture. No AR's or AR builders were harmed in the making of this post, and no offense intended )
If I was depending on an AR for my family's life or other self defense, why would I buy someone's homebuilt version rather than spend a few hundred dollars more for one from a respected manufacturer with well defined QC processes and thousands of rounds tested?
If it is just fun for plinking, don't I still have to make sure the barrel nut was torqued to spec, headspace etc etc etc? So why wouldn't I just put one together myself and get all the parts I want in it and know for sure it was done right?
Parts are just that, parts. Jose in a factory has no special assembly skills that I don't have.
That and it's as simple as a Glock.
Now the machinist making the parts??? That is the real question.