[newscracker]

Fastmail is also terribly expensive if someone wants multiple mailboxes (with separate user credentials) rather than aliases to a single mailbox. With what would cost me several hundred dollars on Fastmail, I can have that and more on Mailbox.org and Posteo.de (the latter without custom domain support).

The disappointment you've felt here is the same I felt with Fastmail. So I decided to move to Posteo instead and save money.