10k got here faster than I expected, after buying in late January. Mine is an 4x4 FX4 3.5L Ecoboost, Supercrew, 3.73 gears, 5.5' bed. It still has the 20" Pirelli Scorpions on it.
With a mix of in-town and freeway driving, I'm getting 15.7 mpg at the moment. On the last road trip, which included everything from light off-road, to city driving, to cruising at 80 on the Interstate, to a couple of fast passes where I had to punch it, it was right around 17 mpg. Steady speeds 70 or less it would run 18 to 19, depending on terrain and wind direction.
A 3.55 axle would have been a bit more economical, but the Eco has considerable mid-range torque, and with the 3.73 it will pull a significant hill without downshifting. The 2wd versions also should do a touch better on economy.
The only real flaw I can point out would be sometimes the Dual zone A/c changes settings, but that's realistically about it. They are expensive trucks, but I am largely satisfied with this one.
