Ask away!! I know I do! The search function sometimes isn't too functional....
We purchased a used gas coach, mainly because it was in our price range. After several years of looking around, we found that gasoline coaches are definitely lesser expensive than their diesel counterparts. You do sacrifice some power by going with gasoline, and they are louder when going down the road because the engine is mounted in the front. Not sure I can adequately compare the ride quality for you as I have only ridden in one diesel unit, one time. I don't recall it being much better than our gas coach. As for cost of operation, diesel fuel is more expensive than gasoline in most places, but you tend to get slightly better fuel mileage with diesel so it will probably equal itself out. Maintenance is probably more expensive on diesels because not just every service station can work on a diesel engine. As stated above, diesel engines hold more oil/coolant than gasoline engines and have unique mechanics. Of course, if you do your fluid changes yourself, you can eliminate the major expenditure of that routine maintenance. Although not always, you typically have more towing capacity with a diesel due to increased horsepower and torque. And, diesel engines tend to last longer than gasoline.
As far as the interior of the coach itself, I doubt you'll see much difference in the quality of the build from diesel to gasoline units. Again like said above, find a floor plan you like and then decide if you want a gas or diesel engine. In the end, it's more about personal preference and pocketbook capacity. Most people I've talked to say that if you're going to be a full-timer and make cross-country trips, then diesel is the only way. Others say gasoline is more economical overall and if you're only making 1K mile trips or less a couple times per year and not towing a heavy trailer or vehicle, you're better off with gasoline. Kind of like a wall...it's up to ya!!