"RIDE QUALITY" is based on "unsprung" weight = what is below the springs - and the type of springs.
The best current tech for a good ride is air bags and independent suspension.
Unlike some posts here have stated, I submit that high weight is actually the enemy of soft ride vehicles. But it's a RV, so what are you gonna do?
Diesel Pushers most often have air bags...and some (not many) even have independent FRONT suspension. The rear is never independent in most RV's.
Gas RV's are more like big pick-ups with steel springs on all 4 corners. That costs less and take MUCH less care.
So, to make a gas RV ride like a DP, the owner needs to consider getting air ride. It is not cheap, but is available in the aftermarket.
Having said all that, our Workhorse W24 rides extremely well. It rides even better when the RV is loaded as to exercise the springs at their rated capacity.
Will we get air bags? Right now we are seriously considering it. Not because the RV rides too rough, but because the roads seem to be getting worse and worse every year.
Anyone actually install a Kelderman System?
The next generation of quality ride will come from reactive hydraulic suspensions...where a computer will scan the roadway and adjust hydraulic struts to provide a perfect and level ride. These will come to premium RV's first...guess which RV's (gas or Diesel) does that mean
P.S. Brakes, ABS, and steering systems add to driveability, but that's different from ride quality IMHO. ABS is common on most all modern RV's and steering aids (Safe-T-Plus and similar) are a good idea for any RV. We have both on our gasser.