IMHO, Blast from the Center non-ducted a/c is WAY louder than ducted.
Plus ducted a/c allows for better temp control and better distribution.
And you can close off ducts to areas you don't need to cool.
There is NO advantage to non-ducted other than cheaper price.
Our 1st hybrid was just a center mount, the new one is ducted. My opinion is that the sound difference is not much. The AC unit running noise is the about the same but the fan noise is a noticeable difference. Running through the foam roof channels softens the sound, and gives you better options for customizing where you want the cool air. If I was buying a new one today...ducted...
A ducted system, also known as a central aircon, is made to cool air in the entire space. It has a central unit where the airflow comes from and is distributed by multiple ducts in different RV areas. These ducts can be placed either in the RV’s ceiling, outside, or under the floor if you’d like.
A non-duct air conditioner, otherwise known as ductless AC, is a replacement for the traditional AC unit. This device has a box, it absorbs the heat inside the room and transfers it to the unit outside.