So far:
* imap search is inferior to gmail (slow, no "did you mean"), but I can live with it.
* greylisting is a pain, but I can live with it. Actually I'm on HN right now after alt-tabbing to wait for a "confirmation e-mail" to come through. Ironically, for an account on the mailinabox format to discuss spam issues :) which brings me to the real problem:
* SPAM. I assumed the spam filters would be worse, and I could live with that. The real problem is that it's a total black box. I have zero insight into how it works, or even IF it's working. Just drag into "junk" and hope for the best. It's very frustrating, and if this continues, I'm not sure if I can live with it :(
I'm getting ~10 messages per hour from the same sender and they all get through. I have dragged >100 of these to the junk folder, used some incredibly obscure command on the box (from a 4y old github issue) to see if it's actually being "counted" as spam at all: it is. Now what? Clearly something is wrong; either this filter is as dumb as a bag of nails or it's not working correctly. Good luck figuring it out. I have no idea where to start debugging.
Essentially, the promise of MIAB is that you shouldn't have to look under the hood. Hosting e-mail is notoriously hard, and they're trying to abstract it all away. The problem is: it's hard because the old tools have terrible UI. Absolutely awful. Arcane unix commands, weird process names, no visibility into nothing, incredibly unintuitive, config files all over the place, log files all over. Sure, it's open source, it can all be learned. But the mental overhead is equivalent to learning a new programming language. It's harder to learn than something like Photoshop, which, honestly, is not OK for what it is (messaging and spam filtering).
I'm weary of the direction this is going in. I'll give it another few weeks, but I'm afraid I'm taking on a responsibility I don't have time for. I don't want to manage dovecot, spamassasin, and what not; they're a full-time job. But with MIAB, at the end of the day, it's not really abstracting it away. It's just a nice setup script. In the end, you're still managing all that cruft, and when push comes to shove, you're on your own.
I advise against it :( Unfortunately.
Hopefully, one day, someone will make a holistic spam server for the new generation. A holistic system which handles everything: outgoing and incoming, SMTP and IMAP, TLS, spam filtering, storage, backups, user management, attachments, greylisting, logging, catch-alls, domain forwarding, all of it in one tool.
The danger of using different tools for everything is incompatibility. E.g. I'm using a lot of forwarding rules, internally. It might very well turn out that spamassasin has a hard time following those rules. Will it understand the internal forwards are not to be marked as responsible for the spam? that the first external received: line is the one to block? I have no idea. And I don't want to worry about it :(
I'd love to pay for a piece of server software which took care of it all, holistically.