Are you planning to give Davemail a try?
Some people are comparing Davemail to how Protonmail works, but there is a major difference between the two services. Davemail is completely decentralized and uses the git distributed version control system to send and receive messages, rather than relay servers. Quite an interesting concept to say the least, although further development of the service is needed to make sure this protocol will have a chance of mainstream adoption.
http://themerkle.com/davemail-offers-encrypted-decentralized-email-services-for-all/
