At 170,000 miles now, this truck runs like new. The 4.8 motor has plenty of power, and still gets upwards of 22mpg - although it doesn't do as well in town driving (maybe 14-15 mpg). But compared to other full size trucks, that don't get as good mpg, and some have less power, this truck can't be beat.
Highway gas mpg 20-22mpg at 75 mph. Easy cruise control. Tough transmission. The engine still sounds new, from start to turning the truck off. Very smooth shift, plenty of power.
Seats area little uncomfortable on long trips. The center console push button breaks easily, and not cheap to replace. Fuel gauge in tank stops working on almost all these GM trucks around 100,000 miles and costs lots to fix (even though the pump still works fine). The pump and gauge are one unit.