The 6.0 motors are a good motor if they have been fixed. They were designed with far fewer head bolts than what they need. The fix is cheap.
I have the 6.4 F450 drw quad cab and love it. Diesel motors last 3 ~ 4 times what a gas motor will and has way more balls. Gas mileage however might be an issue. I get 8 to 9 miles a gallon hauling a 16 foot enclosed trailer around.
Maintenance is also more expensive when needed. 100 dollar oil changes, but every 5 thousand miles. Will post more later. Am at a theatre.