Observations: IF you plan on towing a car (And even with a "C" I suggest it) Then Diesels typically come with 10,000 pound hitch ratings and usually can tow right close to that amount
Max tow is the lesser of hitch rating of difference between MAXIMUM GCVW of Motor home and gross weight of Motor home, IE: on my Gasser the MGCVW is 26000 and the scaled weight 22000, so I can tow 4,000, hitch rating is 5000.
And I just gave you typical numbers for a gasser too.
With a Diesel the engine is often 20-30 feet behind you. So less noise going down the Hwy.
Cost of Gasoline v/s Diesel fuel is debatable. MPG differences as well and I'm not current on the math so can not compare for you.
Diesel engines are often good solid Semi Truck engines, Designed to run hundreds of thousands of miles.. Gassers may not be so durable, (or may be if properly maintained).
Gassers cost less up front. And repairs are generally cheaper.
However in my case the difference was.....
I have worked on gas engines, everything from minor adjustments and spark plug changes to major overhauls I have never worked on Diesels save for installing a block heater on one. Only driven a diesel once, and only for a couple hundred yards..
So I'm more comfortable with a Gasser.