Ask HN: Gmail alternative? gsuite vs. fastmail vs. kolabnow etc.

Ready to dump gmail and pay for email service. I'm willing to pay <$10/month. This is really about wanting to own my own email/calendar data - I am not going to host my own, and given how important email is, definitely don't want some fly-by-night operation.

any thoughts as to what is the best way to go? seems like gsuite, kolabnow, fastmail, and outlook/office365 are resonable offerings, any others i should be looking at? any reason one is significantly better than another?

Requirements:

-migrate old gmail

-strong calendar app

-good web interface and iphone compatible (own app or native mail/calendar app)

-would prefer tagging vs folders for organization

-Reputable company with strong security