Long ago I installed a small server for a university project that ran on linux (slackware with many customizations), at the time configuring postfix, dovecot, exim, etc. Was a pain and probably not worth my time for what it was used so we decided to go with Hula which at the time looked promising, was dead simple to get working and fairly performant given the low end spec of the server (P4 1.8Ghz, 256mb RAM).

Later on Hula struggled badly with Novell, was sold and forked, we tried to check out the forked version (Bongo I think) but so far the project seemed dead.

After a while we did a clean setup after failing a distribution upgrade (but hey 5 years updating without hitch on custom kernel and compiled software), we moved to debian to lessen maintenance, email was done via postfix+dovecoat+postgresql, which was a hassle (to say at least) to configure, funny enough this setup did not perform well, looking for a more consolidated solution we found Apache James, which looked fairly promising (being under the Apache foundation), the only downside was that it was written in Java, not that I have anything against it but that is another vm to install and maintain, we gave it a try and we have been very satisfied with the results, easy to administrate, very sane defaults, relatively easy configuration in case of tweaks (having it use our postgresql db for users was pretty easy compared to postfix/dovecot), it sucks a lot of memory but the machine overall feels even faster that with the postfix/dovecot stack.

So yeah, while its nice to have an email stack that follows the Unix philosophy, it can get very unwieldy for simple setups (while it may shine on complex setups where flexibility is needed).