I traded in a '98 E150 with the 4.6L V8 engine that had 143,000 miles on a '98 E350 Chateau with a V10 and 53,000 miles. The 350 drives better and the interior is nicer. The V10 has great torque and is quieter thant the V8. Gas milage ranges from 11 City to 16 Highway. This van is set up for towing not good gas milage. We will have to see how the V10 holds up.
I ordered this vehicle with all the bells and whistles. The 7.3L Powerstroke diesel is everything I expected. Fuel mileage ranges from 15.5 mpg in the dead of the winter to 18.5 - 20.0 mpg in the summer months. The engine supplies plenty of power and the transmission performs flawlessly. It handles well and has a good ride despite the 1 ton rating. Maintenance cost is typical and I encountered nothing unusual in repairs. This van weighs in around 7950#, so it is no lightweight. In fact, since everything is heavy duty, it tends to go further before replacement is needed.