I have a never ending email battle going in my life. 

1. Hey.com - best interface and service in general, but mail only
2. Fastmail - Nice, economical, but for some reason bores me.
3. Proton - Secure, a little pricey, don't know if I really need the encryption… I don't think I have ever emailed someone where I needed it, or they did.

I'm leaning towards Hey again because they announced they have a Calendar in the works... I really need to pick something and stick with it for eternity..lol