I'm not sure where you're spending time on maintenance. I set up my current mail server 3.5 years ago (postfix, spamassassin, dovecot, sieve, roundcube) and barely ever touch it -- the only maintenance required is the very rare security update.

I use tarsnap for backups, so no tapes required.

I don't love running my own mail server, but as a hacker, I don't see that any of the alternatives are better.