My '13 is the 6.2L with the 3.73. I use it for my landscape business so its pulling a trailer pretty much 95% of the time its on the road. Its been a fantastic engine. The whole truck has been great. I have about 53,000 miles in 2.5 years.
I had been using it to pull our Work & Play. We raced ATVs 14 times per year. The W&P is around 10,000 lbs. loaded and that started to get really old with that many trips. I felt I was working the truck to death between camping and all my business miles. The truck does pretty well but if you've had a diesel, its two totally different worlds.
MPG was around 7.5-8.0 if I kept it under 65. Close to 70mph and it drops like a rock.
Around town and as a daily driver, I much prefer the 6.2. Hitting the interstates and longer trips, I pull out the diesel.