I just purchased a 2008 HR Scepter 42 PDQ that has air leveling only.
My previous rig (2003 DSDP) had jacks only. I found that at my home pad I had difficulty getting level (my fault for using a shoddy contractor) and many times had to move the MH to get it level, usually with the front wheels off the ground a little to a lot or put boards under the front jacks.
My current MH levels in the same spot with no problems. Most air leveling systems seem to give you between 6 and 8 inches to level, about the same as jacks.Maybe I'm just getting a little bit more than my jacks since it levels easier??
I am planning to level out my home pad just for convenience though.
Chris