The f250 will get about 11-12 mpg around town and 16 straight highway unloaded. It will probably get 7-8 towing depending on how heavy your foot is. It will also ride rougher. Other than that it will be a better towing experience not that the f150 would be a bad one.
If I was in your shoes and had no plans to go to a bigger trailer and was happy with the ecoboost I would probably keep what I had or get another ecoboost.
I drive a f150 company truck and own a 2500hd silverado as my personal vehicle and I can tell you I feel a big difference in the ride.