Welcome to the forums. Plenty of answers in that search box at the top. It comes down to size... under 36' you'll be in the gasser size. Over 38' you are in the diesel size... yes there are some 34' diesel, but they are rare. 36' to 38' is a tossup for some but I'd still go diesel for all the other things a DP (Diesel Pusher) gives you. More CCC, air brakes and air ride, and usually better construction. If you do your own maintenance then the better MPG of a diesel offsets the increase volume and cost of engine items. Rarely does anyone go back to a gasser other than to get a much smaller unit.