@lupetalo why do you think that?
@ Spacedust
It's not that Qmail isn't stable or fine, but the ease of the configuration and being able to troubleshoot issues is much easier with Postifx than with Qmail. So the ease of maintenance is very important to me and for many others. Even though Kloxo-MR takes care of everything, there are situation where this is invaluable to avoid downtime of the server! Documentation is also another pros of Postfix vs Qmail.
Postfix is also much more actively developed
There must be a reason why one can't find Qmail packages with Linux distros.
No ! Qmail is just fine - stable and now works with IPv6, but Dovecot instead of Courier-IMAP would be fine.