We're the 2nd owners of this car; we picked it up at around 63k.
In the last 1.5 years, we've definitely had a few things go wrong with it that were out of the norm.
1) Ignition coils 3 & 3 went bad and had to be replaced along with corresponding spark plugs.
2 of the 3 seat belt housings in the 2nd row seats broke.
Seat belt mechanism still worked though.
3) Rough idle
due some minor sludging; this was remedied with a good fuel injector cleaning and oil change.
4) Catalytic converter kicked back a low performance code and was subsequently replaced.
Good thing we bought it from to include an extended warranty which covered it all.
Sad, but we really like the car otherwise.
Comfortable and easy to drive.
The 2nd row bench has plenty of adjustment options.
The 3rd row has suitable even for adults.
It drives better than the Toyota Highlander that we were also considering.
GMC really needs to take a strong look at the build quality issues.
We also have a 2007 Yukon XL that we bought new and never experienced problems like this.
Also, the headrests are just stupidly designed; they're so canted far forward that it's impossible to sit in a fully upright position.