I traded an '04 Chevy Colorado. The Colorado was a little too small. The Sierra is pretty nice. Highway mileage is 18-19 and city is around 15mpg. I bought a sport-side because it looks good. I knew the bed was obviously smaller but the main drawback of the small bed is the lift over when you are standing on the side of the truck. Too much reach is required
My favorite thing is the engine and the transmission. They run and shift very smooth. Also the quality and resale value is high compared to other domestic trucks
GM or some company ought to build a small truck with a diesel engine. It would be very cool, useful, and economical...what are they waiting for?