Buy the new one. 6 year newer roof fabric, newer appliances, tires, brakes and running gear. You will get a full 1 year warranty plus the opportunity to add a second year right from Forrest River for not much money. Not so sure if it will have better insulation or better quality materials but it will be new. The Fleetwood Mallard is no longer being made. The original Fleetwood company went out of business. You won't be able to get new decals, trim or any of the proprietary parts that might be needed. It would be an easy decision for me.
B.O.
