[mmh0000]

The biggest factor was support.

I emailed both Fastmail and Proton with the same question before giving them money.

For Proton, I sent the following message: Hello I am looking to move my self hosted email to a managed provider but I currently have 12 vanity domains. Even your most expensive plan doesn't allow for that many domains. Is there a way to get approved for more domains? I would like to do the Proton Unlimited plan and would be willing to prepay for two years of service.

For Fastmail is was similar but adjusted to account for their plans.

Proton took 7 days to respond, then, the response I got was just a hand-off to a different team. I never did get an actual answer.

Fastmail on the other hand responded in less than a day, and, had a trial period that let me verify everything I wanted would work.

[selykg]

Fastmail has been about the same for me with speed of response. I don't have to reach out to them often, but when I do it's always quick.

They also don't have a limit on domains. I haven't seen any price gated functionality or any limits. I don't have 12 domains, but I do have a handful and it all works quite seamlessly.

I have been with Fastmail for probably a decade or more now. Worth it.

[arp242]

There's a limit of 100 domains, plus 1 for every user in the account.

https://www.fastmail.help/hc/en-us/articles/1500000277382-Ac...

Probably mostly there to prevent rampant abuse from spammers, scammers, or people just doing really weird shit creating millions of $thing where everyone else has a few dozen or hundred.

[selykg]

That seems reasonable. But nice catch. I didn’t know that limit existed. I have 6 lol. Long way to go before that limit impacts me