There has been a ton of discussion about this topic in the past and you may wish to do a search and read all that has been posted.
The short version is if the bus does not have the Prevost over the road AC system (whole coach) cruise airs may not function properly when traveling because the condensing units will be picking up the heated air radiating from the highway, and in some cases that air may be so warm the units will shut down due to excessive temperatures.
The roof air units will be in the cooler ambient temperatures while traveling and could be expected to work better.
When parked and the air intake for the Cruise Airs is in the shade beneath the coach this is not an issue.
Roof air units are cheap and readily available. They may be noisier.
As to original shocks and airbags on one versus the other.....you are looking at about $1200 to $1500 in parts and perhaps 12 hours of labor to replace them. So it boils down to the fact that you may have to spend that on the one coach for peace of mind. Personally, I think their life is gone by 10 years and if I were to buy a coach without good records or evidence the air bags and brake chambers are very recent, I would replace them and be done with it. Both are critical. Shocks less critical.