My son bought an F-150, short box, crew cab, FWD with the V-6 Eco-Boost. He has been averaging 19 mpg city/highway combined with an open box. When it comes to driving I'm a bit more conservative than he is. I'm sure I could average 23 mpg or better with the same truck. I'm thinking driven conservatively, a long and tall Transit with the Eco-Boost should be able to average in the low 20's mpg wise. Plenty of power, although I only drove it once, unladen. I did gouge on it and there was no turbo lag.
One drawback I see to this engine is when one or both of the two turbos goes OTFL. I imagine this won't be a cheap repair bill. Does anyone know what the average life expectancy of these turbos are? From my limited experience, I believe the Eco-Boost would be a great engine for expediting, whether it is in an Econoline or a Transit. I guess time will tell about the longevity of the turbos and the engine.