Not the model years your looking for, but I give two thumbs up to my 2012 eco boost !  Smooth, quite, powerful, and just fun to drive ! Newer  models with 10 speed transmissions ? Wow, they must be really outstanding ! 
The super crew has so much room inside, maybe to much...LOL ! 
Back then I was in the same boat your in trying to decide between a 1/2 and 3/4 ton. With both the wife and I working, we were taking five trips a year, and all within a days drive. So for 10 days a year we needed a tow vehicle , the other 355 days we did not ! 
I was, and still am very happy with our decision to go with the F 150 Eco !  
Good luck !