I would wait for the V10 if you're planning to tow-especially if more than local trips for you. I have one of the smallest lightest class Cs currently available with the V10. Most I ever tow is a Harley on a small trailer. I would not want any reduction of power-or in a practical sense-more engine racing from a smaller engine.
I could live with the V8 power if I had very limited elevation changes, lack of winds, and other real world conditions affecting motorhomes. Specifically the smaller engine would work for me if I was driving locally in benign conditions.
The V8 would probably be fine in lower profile true class B coaches.
