loved the truck until exactly 40,000 miles. Right out of warranty the sun shell in the transmission wore out. Repaired it for $500 in parts myself. Non-mechanics will find no one to do it, and if they do, likely triple the cost. Also had a ticking sound like a valve from about 20,000 miles. The dealership happily checked it out and even replaced the lifters as a best guess. That lasted 100 miles and the sound returned. Seems to not affect anything and can be heard on only a few of the trucks. Unless you haul, don't get the hauling suspension. You can easily load the bed with solid rock and roll down the interstate like it wasn't even there.
The LS-1 based Vortec motors are outstanding. Great design and power. Pulls 75 down the interstate at 1800 rpm and almost 25 mpg. Outstanding for a full size truck.
4L60E transmission is weak in parts, also better assembly in the reaction gears would be nice. Make the new hybrid and quadrasteer available to the guys who need the lower gas costs.