F-650 Opinions

if your doing that might as well get a single axle class 8.

 

We have 2 older F550 ate work that we use with 28' goosenecks. They both have over 230k and still runs good. Are trailer get loaded anywhere from a few hundred pounds to around 40k. Th3 mileage is around 10mpg loaded or unloaded

 

The benefit of a medium duty is better handling, braking and better durability. The down side it's going to use more fuel than the same thing in a pickup line of truck. Reason being it's heavier so with the same engine trans combo they are going to use more fuel. They are also going to be more expensive to license. The truck is heavier so you have to licenses heavier to carry the same weight.
All in all I think the medium duty wins out if you don't count fuel(better durability out ways the extra cost). BUT when you factor in fuel its going to coast more to operate if you are running the same engine trans combo. I've pulled gooseneck so with both a 1 ton and a KW T300. If I were going to to pull everyday with one I'd much prefer the bigger truck. It handles and brakes A LOT better.
Another thing to consider is seating position. You sit up in a med duty and have better visibility with better mirrors.