As was said earlier find the floor plan you like and then if its a gasser fine if a diesel fine. I have a 36' gasser and it has more storage than many diesels of the same size. Only one thing that wasn't mentioned regarding the diesel MH is the Air brakes. You will require an endorsement on your driver's license for the air brakes. This involves taking and passing air brake course before you can legally drive it. Which may or may not delay being able to drive it. In addition if you become sick etc.. (heaven forbid) while you're out and about does your significant other have the endorsement as well to be able to drive it home or to a safe location while on the road.
This unfortunately never gets mentioned in any of the diesel vs gas MH debates.