Just a little update on my ecoboost since an ecoboost was originally an option for OP.
So far, it has been great. I did put a tuner on it, 87 perf/ tow from 5 star tuning. No mpg increase that I can tell but more power and more importantly the shifting strategy is much better. I get around 23mpg to and from work and over 21mpg average.
Towing is very impressive, it makes my old 5.4 seem like it was a 4 banger. I can just set the cruise and run down the highway at 75 with ease. Mileage while towing is what I would expect, somewhere in the range of 14mpg using cruise running 75mph towing a bit over 6k estimated. Ford put in a lot of little gee whiz niceties for towing, nothing earth shattering just makes life easier.
I haven't had any real issues with it. I did have it reflashed and had to have the intercooler replaced under a TSB.
Overall, I am very pleased with the truck. It is nice to be getting that kind of mileage while paying for cheaper gas instead of paying for diesel when I do not tow that much.