The 4000 is a foot longer and a little heavier, but we get consistently around 9.2 while towing a 4700LB toad. The worst mpg we have gotten was 8.7 on a 1000 mile trip into a head wind both ways. The best was 9.7 over about 1800 miles. These are mostly interstate trips where I tend to drive mostly around 72 mph. I'm sure I could do better on mileage a little slower. We are not yet retired and feel the need to get where we are going. We had a few initial issues that took our dealership a while to repair, but nothing that made the coach unusable. For the last year and a half it has been totally reliable.
Vicki and Mike, Aria 3901- The Wined Up Bus