WELL, I HAVE a NEWMAR. And, I could write a whole page on how it forced me to learn a lot more about fixing RV things,....more than the previous five SoB's ever taught me. I thought I was expert, but now it's clear, either you never quit learning, or you quit.
Forget quality control. It's more important for the manufacturer to first make sure that the primary structure be of sound design AND that the appropriate materials are expertly selected. THEN, you can talk about quality control in the construction.
I would have to write a book in order for me to explain specifics.