Which IMAP server to use for virtual hosting?

[Stephen Matlick]

I apologize up front if this is not the correct list to post this on.
 
I am currently running FreeBSD 5.3, Postfix 2.0, and MySQL 4.1.  I am now in the process of deciding which IMAP server to go with.   I did originally install Courier-IMAP and played around with that, deinstalled it and then installed Cyrus-IMAP.   
 
My needs are basically:
 
-  Autocreation of mailboxes when either a user logs in for the first time to check his/her email, or when an email is sent to a new user.
 
-  Virtual domain hosting
 
Security is of course another issue, as is ease of installation and maintenance.   
 
I know most people have their favorites and stand by them, but from an objective standpoint which IMAP server would meet my needs above?  It also doesn't have to be either of the two I tried; it could be one that I haven't even looked at yet.
 
Thanks in advance!
 
Stephen Matlick
Corwin Distributors