My first full sized truck. 5.3L engine has been great. The truck has 80k miles and has had very few mechanical problems. I easily average 16 to 18 mpg around town and 20 to 21 mpg on hwy which is darn good for a full sized truck.
Comfort and power plus fuel economy for a large vehicle. Excellent overall reliability so far (7 years and 80k miles). Great engine/transmission access and design. Good brake design. Good tow vehicle.
Wind noise from rear side windows. Paint clear coat (I've noticed minor defects as it ages). The single mechanical problem has been the drivers-side power window motor/cable assembly. I've changed it twice. Unacceptable! Drive shaft slightly imbalanced at low speed towing uphill.