Any suggestions on a pop-server?
The Cyrus server also offers POP access. Turning it on just requires un-commenting one line in the configuration file. If any user ever requested POP, that's what I would do, but no one has, because...
1) Nearly every popular email client system now supports IMAP.2) IMAP is nicer for the user, since not just their inbox, but their entire folder hierarchy is stored on the server, and is thus accessible from any computer they log in from.
The only use left for POP I can think of is for an ISP that wants to keep disk space used by users' email to a minimum.
So while I can assure you that the Cyrus software does support POP, I have no idea how it compares to other POP servers; I've never "shopped" for one.