I absolutely love Fastmail. I moved off of Gmail years ago with zero regrets. Better UI, better apps, better company, and need I say better service? I still maintain and fetch from a Gmail account so it all just works seamlessly for receiving and sending Gmail, so you don’t have to give anything up either.
I moved from my own colocated 1U running Mailcow to Fastmail and don't regret it one bit. This was an interesting read, glad to see they think things through nice and carefully.
The only things I wish FM had are all software:
1. A takeout-style API to let me grab a complete snapshot once a week with one call
1. hoping to have a JMAP archive format at some point which should cover that. I'd hope that normally you'd be fetching a delta update rather than the whole thing. We've got enough bandwidth for a few people do to it, but I wouldn't want every customer pulling their entire archive every week of 99% the same immutable data; that would be kinda sucky.
2. yeah, I'd love that too - we're keen to integrate with everything else that people are using. We have a basic in-house IdP thing for our own staff to authenticate against our hosted services, but haven't scaled it out. This will happen eventually, though I've been burned enough times I don't want to promise a timeframe.
I use Fastmail for my personal mail, and I don’t regret it, but I’m not quite as sold as you are, I guess maybe because I still have a few Google work accounts I need to use. Spam filtering in Fastmail is a little worse, and the search is _terrible_. The iOS app is usable but buggy. The easy masked emails are a big win though, and setting up new domains feels like less of a hassle with FM. I don’t regret using Fastmail, and I’d use them again for my personal email, but it doesn’t feel like a slam dunk.
