I have a 2017 Ram/Cummins/Aisin/4:10/4x4/air suspension.
If I were to do it over I would have ordered with the std. suspension. The air suspension works fine but Helwig does not (Nor Dodge) make a rear sway bar for these trucks which I miss. The air lines for the airbags are attached to the axle where the sway bar would mount. At some point I will re-work this or delete the factory air and have a larger spring pack installed. I think the air ride is probably better suited to a 5th wheel instead of a heavy truck camper.
With the camper we average 10.5 mph in varied and often hilly terrain.
Not sure on the 2018 trucks but in 2017 you needed a dually with 4:10 to get the highest torque version of the engine if that's important.