So far the only issue I have found on the EcoBoost over an eight cylinder engine is engine braking. It's fine if you pay attention to your descent but if you are not then you need good brakes. My truck is equipped with 3.55 gears but maybe the 3.73's would brake better. Maybe not. Either way it is something to consider.
I am very satisfied with how much power the engine has. It seems to have the same characteristics as a Diesel engine power delivery. I have only towed in Missouri on some decent sized interstate highway hills. But, it pulled my 5500# travel trailer flawlessly power wise. I lock out 6th gear and set the cruise and every once in a while it downshifts to 4th on a long steep hill. It doesn't stay in 4th long though as it picks up speed and pulls on through the hill.
The only concern I have is with the soft sidewall factory Goodyears. I do not have the max tow / max payload. Stiffer sidewall tires are in the near future but other than that I am totally happy with how the truck pulls the camper down the road.