Looking at a new vehicle in the near future and the GMC 1/2 ton with the 3.0 really caught my attention.

Who has one?

Mileage? rated at 22 and 26, others talk of closer to 30 real world.
Mechanical issues? Its been around for 2 years now, not exactly long term but whats the word on the street?
looks like an oil change on this motor is about double at the local dealer, 150 bucks????
DEF fluid, how much we paying per gallon and approx what cost per tank of fuel or per MPG?
Any starting issues in cold weather? lowest I might see here is -25 at night once or twice a year.

According to the salesman, about 8 months out, Wowza.