I have a GMC Sierra I bought second-hand with the optional GFX package. I really like the extra exterior/interior features such as two tone paint, stripe on the side, carbon fibre dash, white gauges etc. At first the 4WD did not work, however after a quick cleaning of the connection from the wire bundle to the solenoid on the side of the transfer case, I have had no problems. It came with the 5.3L aluminum block engine and pulls quite hard. Tow/Haul mode is great for uphill towing. The cab had an annoying grinding noise which was quickly remedied with some hockey tape on the cab door latches. Overall, a great work truck and daily driver.
Carbon fiber dash pannel, white gauges, a sharp looking truck. Comfortable on long drives, roomy enough for six 20 year old people to ride comfortably (perhaps a little cramped, ext. cab). Driving carefully, the truck computer shows I get 18 MPG combined. I calculated up to 25 highway, very reasonable for a 5.3L I thought. Warrenty is long gone, however lots of room under the hood makes oil/spark plug changes very easy (the reason I don't have a Ford).
Some things I thought could be better are the dash board design, though simple and trouble-free, it looks cheap and lacks innovation. Also I dont like the factory GM radio. This is an easy fix though - aftermarket deck.
I love the engineering, some of the design is lacking though. A problem GM should really adress.