I bought my Ford F150 EB in July. It is the Max Tow - Max Payload, with the 6.5 foot box, it has 3.73 gears. I had a set of 285/70/17 - E-Rated BFG All Terrains with aftermarket wheels installed the day I picked it up. I had a Bull Bar installed and I got creative with the license plate because you cannot block the air flow up front.
The dash MPG computer shows 14.5 since I bought the truck. My driving includes pulling my landscape trailer around town(1500 - 3500 pounds, about 10% of my driving), some fireroad driving locked into 4x4, stop and go city driving and several 300 - 400 mile trips. 2 of the 400 mile trips was pulling my landscape trailer with 3500 pound loads.
When I reset my trip MPG, I get about 14.5 - 16 MPG with everyday driving. On the trips with a mix of 60 - 80 MPH, I get 16 - 18.5 MPG.
I just turned 6000 miles on my new F150 EB. This motor rocks, it creates useable torque, and has plenty of giddy-up and go. It is also the best gas mileage I have got with a 4x4 pick-up.
A couple of my thoughts for what they are worth.
http://www.snowestonline.com/forum/images/smilies/new2010/kev.gif Upgrading the tires, a must if you are going to use the F150 like a truck. Get the Max Tow / Max Trailer. It is not an F350, but I wanted gas mileage and didn't want another diesel.
My previous personal trucks have included 3 different 1 Ton Super Duties, 1 - V10 and 2 - 6.0 diesels and an 06 3/4 ton Dodge with the gas Hemi. I also drive an 09 F350 4x4 gas 5.4 pulling a single car trailer for my job, about 8000 miles a month. That gets anywhere from 8 - 11.5 MPG depending on size of vehicle and wind.
This is the trailer I'm going to use the next 2 days. A 28 foot Featherlite. I will put on about 250 - 300 miles so I'll see how it does. I just drove it about 40 miles today and it was no effort for the truck. No sway and it just jumps up to 70 MPH. I'll be driving between 65 - 75 MPH.