I’m very happy with it. Also used it for three years with no issue. Proton is probably more “private” but I hated not being able to use a third party mail application like Thunderbird. And using the bridge app was too annoying. Also, proton calendars sucked at the time. Mailbox is just caldav and I have no issues with external invites. Honestly, most people’s risk vector is going to be fine to not be on Proton or the like. Mailbox will let you auto encrypt everything with PGP as well, but you have to give them your private key which to me, made it less secure so I just turned that off.

I’ve used this service for three years. I used the free version for a couple months and then upgraded to the paid plan. It’s awesome. The support is very responsive as well the 1 time I had an issue. And the problem wasn’t on their end. I have 1 domain for my email on Mailbox.org, and another domain with MX setup for addy.io. So when I want to make a new email I just type one in on the fly. Don’t have to create one on the site or extension first.

I can’t talk about their ownership structure. Seems to be one person or maybe a small team. But that’s just a guess.

Is this only for music, or tv shows as well? I find myself shuffling shows a lot and it was nice in Plex to have a smart playlist and exclude shows that had been played in the last X days from the playlist.

Chezmoi has an amazing templating feature to address different files on different machines. It’s worth the time to set up.

You should only have to backup the Postgres database. But it won’t hurt to have a copy of your compose file as well.

This GitHub issue has the steps you should use. And answers all your other questions too.