Yes, you are going to pay more for a diesel pusher....because they are rarely entry level RVs. The fit/finish/equipment is usually way above what the entry level gas models are so you get what you pay for.

Gas motors, with good maintenance, are generally good for 75-100 thousnad miles. Cummins 8.3 300-350.

My rig pulls an open trailer, bays stuffed with race gear and gets 10mpg. There are no hills in the South East for this thing. Set cruse at 65 and sit there about 850 miles at a time. Speed will vary 2mph or so and never shifts out of 6th gear.

Even though mine is a 94 model, all equipment is original...this was a very high line RV when new, so, high line water heater, furnace, frige, ice maker, convection microwave, water pump, etc. Also large holding tanks..100 gals diesel, 100gal water, 60ish gray and black water tanks. 7.4kw diesel Onan generator runs everything at one time...both air units, frige, icemaker, and microwave.

One other comment. On all the gas units I drove prior to buying this rig, the motor noise was excessive. Could not carry on a conversation in normal tones. With the pusher, all the motor noise is behind the rear wheels so normal conversation is possible, as is the stereo volume and tv. Freaks people out when they see the NASCAR race on the tv when I'm driving home Chuck