I have a '15 SRW F-250 crew cab diesel 4x4 Lariat. Around town, it gets around 13 mpg, on the highway it's around 20 mpg. Towing, it's around 10 mpg (WnP 30WLA, just under 10k lbs). Your right foot makes a huge difference.
It does tow great, the exhaust brake is a nice feature, especially in stop n go traffic. I am adding airbags to it this week. My trailer is tongue heavy (TW around 1300 lbs). I have a Reese WD hitch which works well, but would like a little less rear end squat.
My neighbor has the exact same truck but in a 350. The max towing weights are the same, but the gross axle weight is slightly more on the 350.
I'm extremely happy with the truck and would highly recommend one.