Drive train had a clunking sound when rounding a corner and accelerating. Still under warranty, the dealer's fix was to lube the drive shaft yoke. There are TSB's (Technical Service Bulletins) out on this very problem, as hundreds of Chevy trucks, covering many years, also encounter this clunking.
For the most part, the noise has gone away. It's just something you might have to live with if you buy one.
Another nuisance was a vibration, almost like a clunk, felt in the steering wheel. Again, a TSB indicates that the intermediate steering shaft needs to be removed and lubricated. This was done under warranty, and I've had no further problems.
The latest problem I've had with it is a bad fuel sending unit, which is the component in the gas tank that sends a signal to the fuel gauge.
Again, there are many GM vehicles with this problem; do a Google search and you'll see. The problem stems from additives in the gasoline that deteriorate the contacts of the fuel sending unit. This causes the unit to send erroneous information to the fuel gauge. The gauge can read full one minute, and the next minute, it will slam down to empty.
A possible remedy for this, short of replacing the sending unit (dealer quote of $550) is to add some fuel injector cleaner to the gas tank. I did this twice, and it actually worked. I did this only last week, so I can't say for sure if it's going to stay that way, but it appears to have remedied the problem.
I like the roominess of the truck and its' load-carrying capability. I dislike having to park it, though. I previously drove an S-10, which was a great truck. With this one, I don't enjoy city driving it or parking it.
As another reviewer mentioned, the sheet metal is thin. I've dented my third door, simply by accidentally running into a 55 gallon plastic drum. I managed to pull about 2/3 of the dent out using a Dent King tool.
I will switch back to an S-10 when I'm done with this truck.