Both are very good power plants and will get you to any point in North America with paved road access. The Ford power/torque curves peak at much higher RPM which will contribute to higher noise levels when the power is needed. The engine roar can be attenuated with of noise/heat barriers in the engine cover which some coach builders have recently started to include.

The Workhorse chassis did get a bit of a black eye with brake caliber problems that were fixed with a recall. There could still be a few rigs in the world that the recall was not performed on. Just something to be aware of.
Two identical rigs one on the Workhorse the other on the Ford, difficult choice. Ask other owners and they will normally default to brand loyalty or what's in their camp site. When we were search for a coach floor plan was first priority with the chassis being further down the list. More of a want than a need at least for myself.