I currently tow with a 2006 Silverado crew cab with the 5.3l vortec v8. The truck is a 2wd truck with the eaton g80 locking rear. I stopped buying 4wd trucks after a bunch of problems with one and never using the option. I tow my 27 Judge Chesapeake with this truck from NJ to VA. The boat on the trailer loaded with fuel and gear is about 7500lbs loaded. The tow capacity of the truck is 7800lbs so I am pushing my limits. The truck has pleanty of power for me towing here in Maryland. My tows are on flatter ground and not over any mountains. The hilliest area I tow is down route 4 to solomons haha. Towing I get around 9-10mpg but have seen as low as 6mpg towing into a stiff head wind from southern Maryland to Annapolis. (typcially I average about 17-18mpg not towing with a combination of hwy and city driving)
Where the truck is weak is in brakes and suspension. I have stiffened up the rear suspension with air bags and typically tow with 60lbs of air in them. While the brakes arent the best for towing, you are at the mercy of the rubber on the road and they will apply until the anti locks kick in. Good brakes on the trailer are a must when towing this weight with a half ton.
The interior of the truck looks cheap with lots of plastic. Other brands are much nicer here. It does have pleanty of room in the cab for my entire crew though. I looked for a chevy truck after my father had a much better experience with his bow tie over my previous two fords. I am a fan of the chevy motor and transmissions. The tow mode of the transmission makes for good shifting with a lot of weight. It holds gears longers and takes more to downshift. It has been extremely reliable as I have only had an exhaust sensor go in about 100,000 miles.
The truck is about the ugliest body style that chevy ever put out. They made it for two years before sales suffered enough that they retooled. However, I found a good deal on this truck used with very low mileage on it as it was owned by an older man who thought it was too big for him running around town. It is a tool to tow the boat with and reliable transportation.
The truck has been very good to me but I do think my next truck will have at least a 10,000lb tow capacity. I am currently looking at a Tundra with a 5.7 v8 and 4.30rear. 2wd of course.