On an "immaculate.." rig with four years and 40,000 miles use all the bugs should be worked out. I've purchased older used rigs with much higher milage and they have run out just fine. Best advice I can give is a long test drive and a good long pre-deliver inspection; inside, outside, topside and underside. Many folks are also partial to the coach being mounted on the Workhorse vice the Ford chasis.
The Pace Arrow is a top of the line coach and should give you years (miles) of enjoyment; and given the current market--the price should be right!
Saturn Vue pushing a Bounder 35E