Why would a person not be honest?
Consider the amount of weight a SMB, what it is hauling, and extra gear that people add for a road trip, the diesel fuel will last longer and this is the obvious reason that SMB sells diesels more than gas engines.
Look at their inventory of "new vans" on their website, the numbers speak for themselves.
I have had a diesel SMB and the noise is not a big deal at all.
With the windows down, sure it is loud.
Cold starts are loud, but after 10-15 minutes, the engine is warm and the noise is less.
The diesel fuel will last longer than a gas engine.
The gas engine is quieter though.
Good suggestion to go for a ride in a diesel van.
Good suggestion to weigh out the pros and cons of each engine.
Another good suggestion, figure out your application and use of a camper van.
Some rock crawl, off road & fire road touring, some do snow 4x4, some like the look of a real "Tonka Toy", the list can go on forever, but when you do your homework and figure out your specific needs, the right engine type will become very clear.
I like both diesel engines and gas engines.
Peace,
Zugg