I also switched to Fastmail too. Its interface is rudimentary similar to Google few years ago. It has full suite of services like calendar, notes, storage...

What I like is its simplicity which Gmail may bloat with too many features. One notable feature of Fastmail is alias: you can create other emails alias to your main account and use that to create different rules. Super handy and convenient. If you worry about encryption, probably ProtonMail is a better choice. For me, Fastmail is good for my usage.

P/s: if you want to sign up for Fastmail, here is my referral link https://ref.fm/u12211285