Soooo,
Even with my recent issues with my Denali, this my outlook on this.
I don't think its a problem with quality, its a problem with quality control. A company as big as GM shitting out so many vehicles, parts etc, ur gonna have some shit parts no matter what. Working with aircraft, I've seen some extremely overpriced parts brand new that are complete shit.
What keeps me brand loyal is track records. I mean besides the shit ass 4l60 issues (although my 04 has 139k on it and its still going great) GM has a pretty decent track record as far as keeping mass defects down. Look at ford with the 6.0 and 6.4 issues.
This is just my opinion, not trying to be a GM is master race kind of guy. Hell, I've always wanted a benzo but I waited for Mercedes to finally get their shit together and in the 3 years I've owned my Merc, i've had almost zero issues besides a seat belt tensioner.