Depends on the definition of good enough and your intended use. End of the world warfare needs to go bang no matter what you tend to end up at the same place a top of the line ar is complete from the factory of of a top maker whether you put the pieces together or they do.
Im not tooting the bcm horn cuz there are two in the house but atm its the only source of parts diy or not that is as complete known factor in disclosed source and quality.
It really depends on desired goal the bcm's for my wife and myself are intended to best protectour lives in the coming soon years when the worknots have figured out what it has meant to be a leach grasshopper instead or a worker ant...
Ive got other brands like dpms rra colt that run from tack driver range toy and collector item. Some ive built some purchased in whole or parts.
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...