I went with a used, low miles F350 V10 gas. My father in law went with a used F250 diesel. We are both happy, so far. We both tow roughly the same loads.
What got me rethinking about diesel was this experience. One year I took a relative’s Dodge diesel to Colorado with my four horse trailer and got about 10 mpg. I then bought my V10, paid decent price for it because people believe it is a gas guzzler, and took it the next year. Got 9.5 mpg. Roughly the same load. Don’t see how I can pay for the extra cost of the diesel engine or fuel at that small savings. Without the trailer, the Dodge got 16 mpg and my V10 gets about 15. I believe my father in law gets about 17-18 without his trailer in his 7.3L diesel engine.
I can only speak to my own experience. I don’t haul this trailer daily, but I would almost have to use it daily to cover the extra diesel costs, best I can tell.