I think the biggest difference you would note is a more compliant and comfortable unloaded suspension. The air leveling means you can have a quite soft suspension with the springs, and add the capacity only when you need it. Also air springs can add ride height and capacity without adding stiffness to any great degree, so even loaded the ride should be more compliant. I notice the 2500HD option is a fully air ride suspension, not supplemental - that should be very interesting. As an aside I just replaced three of the original air springs on my bus, due to exterior cracking of the surface of the rubber spring. They still worked perfectly, did not leak, and were perfect inside - at 34 years old...
Downside of air suspension is you need to maintain an on-board compressor.
Brian
