I think you want to look at your buildings and their overall condition. When do you think they would be due for renovation? How long would it take for you to see a return on your investments? You will be hard pressed to find HVAC personnel with the expertise and then when you do get them what is going to be the cost? I think best is giving you a couple of sites that talk the pros and cons of putting a unit in. I think these will give you the answer you are looking for:
I have lived in Europe where the systems were used. Since the area we lived in never got that hot in the summer, I had fans and portable a/c units that I signed out on a temp basis. The tenants were not charged for the units unless they lost them or damaged the units. Some elected to purchase them on their own.
My thoughts are I would just figure this technology in on new construction. If all information given and you still want to go forward, then I say you need to vet the installer for experience as well as if they mess up the installation by placing units in which are either too big or too small.
Ductless systems work well in some applications, but won't heat or cool an adjacent room when the door is closed. If the bedroom is on an exterior wall it will make the temperature difference even greater.
The similar systems called mini-splits operate on the same principle. However, they have two separate indoor "blowers" to be installed in different rooms (i.e. one in the hallway and one in the bedroom).
If you try one, be sure that the installer follows the installation requirements precisely or you may end up with water damage to walls and/or floors due to improper condensate drainage.
When properly sized and properly installed they do a great job of conditioning the room in which they are located.
The ones I'm familiar with require a bit more maintenance than a conventional system. The filters have to be removed, rinsed, and reinstalled.