Well, at risk of causing an argument here......
If you're interested in used, I think the absolute best chassis available out there is the 2002 to 2006 Monaco Dynasty, which has the tag axle Roadmaster Chassis, or the 2002-2006 Monaco Windsor, which has the standard two axle chassis. That's my next coach of choice in a few years.
I currently own a 1995 Monaco Dynasty, and I bought it only because I think the Roadmaster Chassis is the absolute best chassis on the road.
Most motorhomes sit on top of a truck chassis. That means the springs or the air bags are directly underneath the frame rails, with the wheels at least a good foot outside of that. Then the motorhome body is bolted or welded onto that. Lots of problems with sway and wind control.
The Roadmaster Chassis places the air bags directly in front of and behind each wheel, almost out at the outside of the motorhome, which means superior sway and wind control. Plus the upper frame of the motorhome and the chassis are all one unit.... a semi-monocoque design.
Another company that I've heard builds their own semi-monocoque chassis is Foretravel. I've heard that they have a very strong full frame chassis.
So, there. My vote for best chassis is the Roadmaster Chassis.
Jim Sanderson
1995 Monaco Dynasty 36'
Canada, eh?