I agree with Advanced Lawn Care we also own both along with a 454 and a Cummins 5.9. We are strictly hardscape construction and stone masons. Every thing we haul is heavy and our terrain is rolling to hilly. We pull every thing with everything. The diesel is king of the tow but the others are no dogs. GM motors are snappy Ford is slow wind up torque pretty much as they have always been. Fuel mpg is nearly equal from low of 8 in heavy tow to 13 on Istate empty. Cost per mile to own is affected more by how you buy than what you buy. I can't get diesels to pencil out, and we don't race from job to job bet you don't either.