I have 2500 miles on the truck. Taken two trips totaling 800 miles getting about 25 mpg on highway and 18-20 normal driving. Pulls 3000 pound boat ok. Seems kind of small from the Z71 ext cab I bought new in 04 but traded for gas mileage and it is doing better than the 14-15 the Z got. If getting the 4cyl, go with the 5 speed if you plan to do any pulling. It will run highway speed with a load in 4th without much trouble but 5th is useless with a trailer. As far as driving empty, it has plenty of power, haven't had to take it past 5000 rpm yet when pulling or passing. Mine has the 3.73 gear ratio I think this is the best ratio as it would be turning a lot or rpms in 4th with the 4.10.
Rides really good and it is quiet at speed. Passing power is good from 50-70 but you have to use 3rd gear. Factory receiver hitch is a nice feature. Ride height of the z85 suspension package is good for hooking up to a trailer.
The seat adjustments feel really cheap as do the back door latches. Use a style like the Silverados, never had any trouble in 3 yrs with them. The cup holders in the front need to be deeper and larger. Only a can fits in the drivers side. Add an oil pressure guage and numbers to the h20 temp.