Sorry to do it, but I gotta say I love my Ecoboost.
I have towed the same 4 place enclosed with my Ecoboost that my buddy has towed with a 6.2 half ton Chevy and 6.2 Escalade.
Ecoboost flat out tows better, without question.
The 6.2s are fast and in an empty drag race should be similar or faster then the Ecoboost. But, the fact is the Ecoboost makes way, way more low end torque and hardly downshifts. The 6.2 is always shifting and likes to Rev. The Ecoboost loves 1800-3000 RPM.
Then you add in the Ford has a far bigger crew cab and gives you the 6.5 ft box option with the crew.
Why on earth would you buy the Chevy/GMC?
I have zero brand loyalty. Last two trucks were Cummins. Truck before that was a GMC. This is my first Ford and I love it.
That being said, I really like Duramax. Looked hard at one and just couldn't justify the cost. Didn't trust the new Powerstroke. I like the Cummins and the fact you can still get a stick shift. However I tried something new and love the Ecoboost.
Also, as far towing 7000 lbs. I wouldn't worry about it at all. My F150 tows a 4 place enclosed great and we towed one with Escalade a bunch. They tow just fine.
Just my 2 cents, from a former diesel owner. I love diesels but the way they rape us on fuel, they are only worth it if you tow a lot and tow over 9000 lbs. Or you own a business were the fuel is a tax write off.