I own a gas truck, my SIL owns nothing but diesels. he and I took a trip once towing our TT's. I gassed up four times and he fueled up twice. same distance, same year truck, one gas, one diesel and his TT was 5 ft longer than mine. BUT there are many posts on this forum from past diesel owners that have gone back to diesel. after seeing my SiL pull his TT, I am thinking going to diesel. so it all comes down to what ever you want, you get. don't think you will go wrong with what ever you decide. right now I'm pulling with a 3/4 ton 6.0 with 4.10 rear end and it pulls good, might take me a little time to climb the rockies but it does what I ask it to do.