Our mainframe is being less and less used, to the point where it seems the only thing it will be doing in a year is servicing JES print requests from our client's mainframes.

We are considering replacing it with an AIX box that has a JES subsystem.

Based on that, what things do I need to look into and research?
I am told (but do not believe) that S/390 JES and AIX JES are the same.
But I though JES was Job Entry System, which means that it could then call amost anything.