I was in the same boat and ordered a 15.
The refinements are what I wanted, not the power.
So far the truck is great.
Fuel economy seems a little low to me.
I'm getting 13.2 in everyday driving, mostly in town and towing a trailer for work or play about 20% of the time.
Just took an 800 mile trip and got 18 at 75 mph.
Talked to the dealer and he said my mileage is low compared to what he has been seeing and to bring it in.
Considering it has nearly 4200lbs payload and rated to tow 16100, it is hard to say for sure what it should be.
Other wise I love it.