Seems like any gasser would struggle with the load you're running. The V-10 is smaller, but lighter and more modern. Like other small blocks, it seems to like revving higher when climbing. It'll be hard to get a good comparison, apples to oranges, so to speak when not comparing the same coach, weight, load, tow, etc. You could always try a short term rental of a coach with a V-10 or try a test drive if possible.
You can google: "chevy 454 vs ford V-10 in a motorhome" to find many forum threads discussing it. Good luck.