I bought the 4.0 litre V6 with auto transmission because it could tow 6500 lbs, 3000 lbs more than the 5 speed manual. I tow a 3500 lb RV, sometimes with a 15 ft boat in tandem. This puts me at maximum combined payload & towing capacity but the truck is up to the task, if I take it easy: about 60 mph on the flats, up to 75 mph downhill. Towing in a headwind, the tranny constantly downshifts but turning the overdrive off helps keep it in 5th gear. A manual tranny would have been better, or more power. Mileage is not the best: about 19 mpg highway, much less in the city. I drive like an old guy, easy on the gas, coasting not braking, and at the speed limit. The truck is great otherwise.
Perfect reliability, 18 to 20 mpg, this truck was a good deal when I bought it and has been everything I could ask for since. I traded in a 3 liter Ford Ranger I called the turtle because the motor (and transmission) was such a slug but the 4.0 is a much better powerplant and the mated automatic transmission is a world better as well. It tows a trailer quite well and has now been across country and back twice. Not plush but a great workhorse truck.
I wouldn't own any othe truck. No one is putting more than 200 horse power in a compact 4d4 truck and offering a manual transmission and a tow package for less than $20,000. My 2001 is going strong after 650,000 miles with no major problems. Engines runs as good as new and has never been worked on.