Just traded my 99 Quad cad, 4x4, 5 speed for an 06 Mega, 4x4, auto. Man I love it.
Anyways, the 99 got 18 mpg empty and about 15 mpg towing.
The Mega got 17 mpg on the highway driving about 200 miles @ 60 mph on the way home from the dealer. It's dropped off to about 15 mpg around town...