Agree with the others here....IMO unless you move to a very high end coach with proprietary chassis, there is likely little difference that you would feel or experience. It is more about how the coach builder mounts the box to the chassis in terms of rigidity, quiet ride, etc.
At one time American Coach was taking a Freightliner chassis cutting it in half and building what American called a 'Liberty bridge' between the sections, thus the name Liberty chassis.
Drive coaches from the various brands, levels you prefer and find one that drives and handles to your liking. Once you get to the higher end coaches with tag axles from any of the brands, I suspect the differences are marginal. Newmar's comfort drive is said to be a nice feature.
My previous coach had a FL chassis and it was just fine. Also, if you live or travel anywhere near the Freightliner Chassis Service Center in Gaffney, SC, they specialize in servicing their motorhome chassis and do a stellar job at a reasonable price.
