I've been using Migadu for about four years. My main complaint is that the support is not good. To be fair, they do not promise to hold your hand. And that's fine, I can usually diagnose my own mail problems.

Here is an example. I have one family member who wants to keep her email address on the family domain but have all her mail forwarded to her address @gmail. So I have migadu forward her mail to google's gmail server. One day that forwarding stopped working. So I asked migadu to check why the forwarding was failing.

They replied that they have no way to do this, and I shouldn't be forwarding to gmail. I've never heard of an email service that can't forward! They pointed me to this doc: https://www.migadu.com/guides/gmail/