It is actually Damon Tuscany. I have been living in a 1994 Damon Challenger 32 foot class A gasser most of this year. I really like it. Damon is in the lower end of the RV market and that is why I like it. I don't want a high end unit with all the bells and whistles. I want a simpler unit without all the stuff that can go wrong. I don't need power steps, slides, central vacuum, levelers, satellite dishes or any of those other frills. Of course they make Damons with all that stuff on it. This one is 18 years old and the engine, tranny and the rest of the drive train is nice and solid.
You are right, diesels last longer. But unless you need the extra power to tow in mountains, a gasser will probably outlive you. You might have to rebuild the engine after 150k miles, but that would still be cheaper than getting a diesel if you don't really need one. However if you do need the power then a diesel is the only way to go. I would not buy a diesel just because it would last longer. The average RVer only puts 6000 miles a year on his RV meaning a gasser would last 25 years at least with proper maintenance.