There really aren’t any issues with the 2007 and later GMT900 SUV’s. About the biggest issue seen in warranty is power door lock solenoid failures up until 2008. The electric shift transfercase, which is standard equipment on full-size SUVs, isn’t the most reliable thing but you have no options to get a manual shift. Pretty much the entire industry is making soccer mom trucks for people that should be driving cars.
The 6.0L has been a great engine with no major issues either. The 4L80E transmission can be hit and miss. Most are bomb proof and will deliver many years and a couple hundred thousand miles of uninterrupted service while others are a turd from day one. Some GMT900 2500 series Suburban’s have the rock solid 10.5” 14 bolt full-floating rear axle while others come with the 9.5” 14 bolt semi-floating rear axle. The latter isn’t the axle of choice while the full-floater is harder to come by. One thing that I personally dislike on all GMT900 trucks and SUV’s is the design of the door bottoms where the door bottom edge runs parallel to the road instead of being protected by a rocker panel. A verticle door edge will chip and rust much easier than a horizontal piece of metal such as a rocker panel. If you live where road salt is used this is a major rust issue that GM has been in denial over since the trucks were introduced in 2007. Overall the GMT900 SUV’s are pretty decent but less plentiful compared to the 2000-2006 GMT800 SUV’s, as the SUV craze was cooling off due to higher fuel prices by the time the GMT900’s were introduced in 2007.
This is what I mean by the door edge being unprotected. I recommend adding nerf bars, running boards or bed liner to protect and prevent the door edges from chipping and ultimately rusting the door to bits. Poor design by GM! Shame on them!