I do like Tutanota's approach to encryption, but communication outside of other Tutanota addresses is less secure than PGP. It's just a symmetric, password-based scheme.

Since you will probably deal with a lot of non-tuta email providers, it's a hard sell for me. In network, though, it's good.

Second issue I had with it was the email client. I like my third party client and it's built into my workflow. Tuta doesn't support third party clients because they consider the storage of emails on your local drive a security risk. (That's only true if your hard drive isn't encrypted, and setting up encryption isn't all that hard to do)