I've been studying diesels for a few years now. Wanted one in a 2005 Liberty, wife at the time didn't. Finally bought what I wanted after the divorce. Went from two vehicles to one, so this is a daily driver and the only viable daily driver amongst the big three IMO. I get 14 mpg city A/C on (with lots of idling and sitting at lights), 19.5 highway (70 to 75 mph). Not bad for a vehicle that weighs this much and can tow 15,400 lbs. Can't imagine feeding the old gas big block! Ride is a little rough on bad roads because of the heavy duty nature. I'm researching how to change that (airbags, different springs/shocks). With a load, it's perfect.
Without a doubt: Duramax/Allison. This is by far the best light diesel drivetrain on the market. Test drive them all; you'll see. I still have respect for Cummins. None for Powerstroke. My interior is very nice. Wish it had the LT2 cloth but could not live without bench seat in extended cab.
Wicked quick truck needs better brakes. Ford's instills confidence, these don't. Towing mirrors are also not as good as Ford's. I wish the ebony cloth did not have a deathgrip on dust. Needs a chrome delete option and bigger factory wheels and tires. All cheaper to fix than a wimpy engine!