well I would say it all depends on the sensitivity of your butt! You are driving a 15000lb vehicle and the ride will not be like in expensive sedan. Speed, tire inflation, airbag inflation and actual weight of the rig will all have an impact on the ride. I have a 12 Winnebago, dont like the seats in it but it does ride ok, I like the ride in my 04 F350 and it is the travel vehicle when we go someplace WITHOUT the rv and towd. Again it will depend on many factors, the roadway itself, railroad tracks and the stuff I mentioned earlier. Class As are really no better as they run up to 120 psi in tires alone! Class c's are 75-80psi.
You want a rough ride, ride a school bus, soft ride, ride in a city bus. Day and night but the city bus seldom goes over 35-40 mph and the roads can be (not always better) My school bus is sprung hard and yes it does bounce over ruts speed bumps so no comparison in the 2 vehicles. One is all air suspension the school bus traditional springs and sometimes rear only airbags.
so again the question is rhetorical and there is no correct answer.