For me it basically boils down to,,Buy what you want.IMO,there is nothing worse than purchasing something and then trying to make yourself like it.
I have made the entire circle,started with a popup,then made progression TT,F'ver and A coach.
Same with with my trucks,7.3,,6.0 and decided I really had no use for a diesel truck so we sold ours and I purchased a Gas truck.
The wife and I are weekend warriors and don't travel great distances,we also ride off road so i'm often pulling a trailer with two side by sides on it.
About 18 months ago sold the coach and went back to a two slide 28 ft TT.Towed with a gas truck.truck performed well and did a great job with my trailers,I'm not knocking gassers in any way.But I simply wasn't satisified with it.
Do i need a diesel? ,,No
Do they cost more than a gas truck ?,,yes
Is maintenance more expensive ?,,yes
will they last longer than a gas engine?probably not with newer gas engines.
But the smile on my face when towing is priceless.