Why Postfix is not my favorite mailer
Today I was unpleasantly surprised to discover that Postfix defaults to having a 50 megabyte size limit on user mailboxes, after which email bounces. This default limit is apparently sufficiently unimportant to not be mentioned in the 'basic' or 'standard' general configuration documentation.
Perhaps this will strike people as a petty reason for disliking Postfix; after all, it's just one configuration option. But it is the symptom of a deeper problem.
Since Postfix people have made one dangerous random arbitrary default (and not drawn attention to it), I can't count on them not to have made more that I just haven't tripped over yet. In other words, I can no longer count on them to have a sane default configuration.
This means that I have to examine the default for every configuration option Postfix has, just in case it's going to eat email in the future. If you have never looked, Postfix has a lot of configuration options; the HTML page documenting them all is over 400 Kb. Many of them will be unimportant, many of them will have sane defaults, and Postfix has forced me to still read them all just in case.
Worse, I can't count on the Postfix people not to introduce more insanity in upgrades (since it's clear that their ideas of sanity are significantly different from mine), so I'll get to periodically repeat this exercise more or less in perpetuity as long as I run Postfix.
So, in short, Postfix is not my favorite mailer because it has made it clear that I can no longer trust it.
(To be clear, I am still confidant that Postfix won't accidentally eat mail. I'm sure that all of the mail eating it may do to me in the future will be deliberate, set up by people who felt that it made perfect sense to eat email in that circumstance.)