As an ex-customer (with Migadu for about a year), I have nothing but good things to say. Customer support was always very quick and knowledgable. It's not a huge team so it has that "I'm a regular" kinda vibe when you chat with them. Obviously I left but it was to try out Fastmail's JMAP (?) format because I had a lot of emails that web UIs struggle to handle. That's maybe the only improvement I could suggest?