I would have preferred the small PABX over the Aiphone that I had installed but I did not hear about it until I had my intercom installed.

The reasons I would have preferred the PABX is that each room would have an intercom facility plus a PLDT line with just one unit. Instead of what I have right now which is an intercom unit at the common area and a phone socket in each room.

I am not sure about the maintainability of the PABX system but the intercom is so basic that there is no maintenance at all. Just make sure that the power source is plugged in and that's it.

I have a tendency to go overboard when wanting something which is why I regretted then not knowing about the PABX system. But now in retrospect, I have a simpler setup which caters to my needs.