If you want to read what users of the service post in a user forum for Fastmail (one of the many customer service features available) then check out
https://emailaddresses.com/forum/showthread.php?s=&threadid=1560
I use several services and have run my own servers. Fastmail gives it all. Go check out their list of features:
https://fastmail.fm/docs/pricingtbl.html
No graphics, no ads and controlled HTML views. Very fast. Only free guest accounts have ads or tag-lines in sent messages. Several paid account levels very reasonable priced. Basic Lifetime accounts available. Configurable signatures and personalities. Have a personality for the office and one for friends and family. Extensive folder options. Built in spelling checker. AutoFormat formats email including bullet points, indented paragraphs, and so on. You can get email from as many external providers as you like using POP. You can redirect (like forwarding, but keeps the original sender intact) as many messages as you want to another email address, rather than having to forward them individually. FastMail doesn’t require cookies, Java, JavaScript, or any other technology. It will work on the browser you find at your hotel room, airport lounge, and TV internet. FastMail provides both external POP and IMAP access! It has advanced filtering using Sieve filters (much like Exim filters).
Fastmail has it all!