Gas engine and low gears. Ford provides the most options packages for hauling and towing. GM trucks have the IFS which makes for a little bit softer ride and tighter turning radius. With DRW I would be getting a 2011 or later GM or a 2013 or later Ram to get their stronger and stiffer frames.
People focus on the engines but most of the money I have spent on repairs has been for suspension components, transmissions, radiators, AC, heater, brake rotors, electronics, and other parts where there is a great deal of difference in reliability depending upon the manufacturer and the model year. Individual user's experience has value but I prefer to review the repairs surveys of the types of repairs by make by model year that are available and then decide if the problem areas are minor or major for a particular make and year.