I’ve been using Tuta Mail for a few years now. No complaints. Most of the features you would expect. Lack of IMAP support is kinda disappointing but survivable. Their email security is very strong though — they encrypt every part of your email, including subject (some providers only encrypt the body). They’re also rolling out post-quantum encryption of email data at rest, which tickles my crypto nerd side.

They’ve still a loong way to go to match Proton’s product suite though, as they only offer Email, Contacts and Calendar for now. They’re working on Drive storage next, which is the main reason I currently use Proton.