@p

Fwiw, the main difference is I use a chain of several RBL's and I shut off addresses which are routinely targeted using postfix recipient_access and sender_access lists. Whereas gapps/gmail allows to filter inbound email into the spam folder, my setup refuses to even accept it in the first place (ie. responds with "550 Mailbox does not exist."). I also have spamassassin, but it basically never gets triggered because there's no spam received. But literally, they're the same exact domains and accounts which were formerly hosted by gmail/gapps, and switching to self-hosting eliminated effectively 100% of the spam and 100% of false positives basically overnight.

Another neat trick which I've been using long before I switched *to* gapps/gmail, is that when I have to register on any website or give out my email address to an untrusted party, I give them theirdomain.tld@mydomain.tld so when I do inevitably get spam, I can easily identify the source of the leak and shut it off. Works like a charm. Also a good source of laughs to see who got hacked or had their db sold to spammers.