My 3.5 Ecoboost Screw with Max Tow (3.73 rear end) is not quite a week old yet - has 350 total miles and I reset the mpg when I drove it off the dealer lot. I live about 10 miles outside of town - and after 6 days of mixed back-and-forth to town plus "in town" driving the display says 17.8 mpg (no towing yet).

I'm hoping for better - we'll see.