I will say I'm quite loyal to GM, while I have had a bad one, it wasn't horrible compared to issues some people have with any brand of car.
I've had the following GM cars:
1990 Buick LeSabre 3800 v6
1991 Buick Century 3600 v6
2002 Chevy Impala 3400 v6
1996 Buick Roadmaster Estate LT1 5.7 v8
2001 Cadillac DeVille 4.6 Northstar v8
1999 Buick Park Avenue 3800 series II v6
2000 Buick Park Avenue 3800 series II v6
2008 Buick Lucerne CXL 3800 series III v6
And currently I have a 1996 Buick Park Avenue with the 3800 series II and the Cadillac XTS
Of the GM cars I've had I was disappointed with the Impala as the 3400 engine was underpowered for that car, had I had the upper trim one with the 3800 I'd of probably liked it.
The DeVille burned oil, the rt. rear brake caliper leaked brake fluid, the transmission was replaced at 58k due to a faulty component, and as soon as it started running warm I unloaded it.
As noticed I've owned every version of the 3800 v6, the LeSabre had 180k and running strong when it was sold, the 99 Park Avenue had 175k and the 00 Park Avenue had 130k and I sold it because it was starting to have some subframe rot issues.
However I was not as pleased with the performance of the series III, it didn't seem as powerful, and I got about 3-4 mpg less in comparison to the series II
I have also had a LincolnContinental, Town Car, and a Ford Taurus wagon. While none of them were problematic cars, I just never enjoyed them like I did the GM products.
I came from a heavily GM family, grew up with them, my maternal grandparents only bought Chevy, and paternal grandparents were Oldsmobile people, but in the end owned a ford.
As stated by someone above I have no reason to not be loyal to American cars, though I tried one import I hated it and will not be straying from GM