7.3 pulling a "toad"....7.8 not pulling a "toad". As far as diesels go, first off, the OP is asking about GASSERS.
While i admit a diesel MH is smoother and quieter, so...what about MPG? Yes...I might be 7.5 (average) and you might get 11....but you're paying as much as 50 cents a gallon more! So....where's the money advantage.
Besides, (more than) enough RVers cannot afford a DP (and that's fine.)According to posters here (and other sites) MAINTAINING a DP is alot more expensive than a gasser. Some of the DP (problem) threads here are scary.