I've driven all three of those trucks in those year ranges and a previous generation(05-07). I liked the Chevy the most, but it is all a matter of opinion.
The LMM Duramax is an awesome motor and it is never low on power from what I felt. It seems refined and smooth throughout the whole RPM range. The transmission is an Allison and never slipped or searched for gears while I was towing.
The 6.7L Cummins is a good motor with decent power but it felt like it was down tuned because of the transmission. It seemed to always lug a little bit right before a shift. Pulling up the hills it seemed to ease into a shift point and it felt sloppy and not crisp.
I've driven but never towed with the 6.4. They are good from what I felt, good power quick acceleration. The only thing I didn't like and I remember almost the same feeling on the 6.0, it seemed to slow down super fast when not in the throttle. Almost seemed like a brake was rubbing or the transmission wasn't warm and it was creating a load on the truck while coasting. Maybe it was just that truck, but I've felt it in Ford's before.
Interior wise I would again go with the Chevy. While you said you like the mid range trucks I don't think you can beat the LTZ package, the LT is not bad at all either. With the center console option and a crew cab there is a noticeable difference from the work truck versions. I had an 08 Tahoe LTZ and the only reason I got rid of it was because it was 2wd. Now that stated the dash did crack on the dashboard in front of the steering wheel. The power door locks had to be replaced multiple times. But over all it was in the top three of all vehicles I've ever owned.
Dodge interiors have nothing to offer IMO, the Laramie and SLT packages just feel like upgraded work trucks. This is not a bad thing if you don't want a penthouse to drive around in. But if you are putting a lot of miles in and want some creature comforts I wouldn't get a Dodge.
Ford interiors are over-rated from what I have experienced. The King Ranch is made from good materials but for me it doesn't offer enough "flair" for the price. The mid range package(can't think of it) seems like a slightly upgraded Dodge. I have grown up a Chevy lover my whole life so maybe I am just biased against them.
Cliff notes: In order I would get an LT or LTZ 2500 Duramax, Big Horn 2500 Cummins, XLT F250 SuperDuty. I say this based on driveability, price-tag and comfort.
