The Air bags (suspension ) as you know provides a comfortable smooth ride .. You WILL notice a large difference in the sprung ride of what is essentially a converted "bread" truck Vs the Bus frame like ride of the DP. Its the first thing most people notice and like about a DP.
I differ on the Brakes .. The heavy Thick air brakes if cared for will go 150000. miles or more on the DP..not so the lighter truck crawl under and have a look The brakes are at their limit more than the DP. Not a bad thing ,just a difference There is a reason air brakes are used on very heavy vehicles .. semis etc.
I note I have limited time in a Gas Motorhome( lots of time.. 8 years... in a 26000lb delivery truck and am a Tractor trailer driver in real life so that is my perspective