I bought my truck new and have driven it for 20k miles. Fuel economy could be better but it's as good or better than any other small 4x4 pickup (24 highway and 21 in town). The truck has a cushy ride, functional interior and the engine performance is adequate. I haul lumber, firewood, dirt, stone etc. and it's holding up quite well. There was a cylinder head problem with the I4 and I5 in model years 04-06 which I understand has since been resolved. GM replaced the cylinder head on my truck at 7k miles. I've had no trouble with it since and GM agreed to extend the warranty on the head work after I complained. So far I'm satisfied with my Colorado and would certainly consider GM again.
Comfortable ride, engine performance, fuel economy, made in US by UAW.
The truck seems much too heavy. GM could easily knock off 500 lbs. without compromising structural strength. I'd like to see carbon fiber replace those heavy bumpers and the bed. That would improve fuel economy, braking and handling.