Get it, now! https://protonmail.ch/pages/security-details ...especially true for sources. I know of no other better free mail service.
Better as in secure. You can choose to send encrypted messages to other non Proton users or not. If it is, they have to follow a link to decrypt. If not, then it's delivered just like any other mail service.
I was on the waiting list for proton mail for about 3 weeks maybe. Just got my confirmation that my account was ready a couple of days ago and set it up this morning. Has to be "set up" on a PC. No phone or tablet. It can be used from anything after the initial setup.
They need to stand alone Android app for email interface so you don't have to use the browser on phone, that would be nice.
Safe-mail, as do most email providers, release requested information when presented with a valid court order in their jurisdiction. Source: http://www.forbes.com/sites/runasandvik/2014/01/31/the-email-service-the-dark-web-is-actually-using/
I am a big fan of unseen , very secure. military, vets, and first responders also can receive a free premium account.
Securenym can't because there's no way to match the account to a specific person. Countermail and Anonymousspeech just flat out won't cooperate with the US government.