Gas vs Diesel

Value is subjective--any new coach will take a big hit the moment you drive it off the lot, what matters is what a coach will bring when you trade or sell it. The point still remains high mileage on a gasser will affect it a lot more than a DP. A dealer will use every trick to give you as little as possible on a trade, and he will take high mileage on a gasser into account when he makes his offer.
I don't use Ebay as an indication of DP sales. They don't sell nearly enough of the coaches we are interested in for our future replacement coach. Nice versions of those have been selling like hotcakes--some not lasting a week.