I'm using paid accounts on both Fastmail and Protonmail. I have settled on Fastmail now for primary use.
Its not as feature rich as some services, but it covers what I need. Multiple account fetch, simple identity management for sending from those accounts, and a basic calendar to aggregate work and personal schedules make it just handy enough.
The idea behind Protonmail is interesting, but Fastmail was just a bit more convenient. The calendar is a differentiator for me.
I'm apparently one of the few that did not prefer Inbox.