I made the switch to diesels 2 trucks ago, my first was a 99 F250 7.3, I traded that in on a 2014 F350 6.7 in 2016.
am I happy with my choice, yes I will never go back to gas.
not realy any 1 ton is going to have higher maintance on brakes, tires, and so on, but my 1999 F250in the 10 years I owned it aside from normal maintance (brakes tires etc that is the same for both) the only repair/ breakdown I had was the water pump which I did myself and was pretty cheep. my 2014 I havent had any maintaince in the last 8 years aside from a front wheel berring, again comon between the gas and diersel trucks. Oh I did have to replace the ccv vent. the problem isn't how much the parts are its how much the dealerships will rip you off to do it.
the side benifit is my old 98 F250 gas used to get 7mpg towing my old trailer, my first diesel towing the same trailer got 18mpg and didn't strugle to get over 50mph in the mountians. I got my new diesel only because we bought a 5th wheel that was to heavy (300lbs over the rear axel) and towing the beast they both get about 15mpg (did one trip with the old truck) I think the 5th is in the 14 to 15K gvw range
when I retire will be my next one maybe it will be diesel, even unloaded the fuel milage is better, and normaly diesel is cheeper than gas also. I added a emissions leagel tuner to mine and if I drive nice empty I am getting 27mpg (Cdn not US)
