The other two are Silent Circle and Lavabit which both used to operate so-called private email services and shut down their services rather than sell out their users. So they placed their reputation and their users' privacy ahead of their financial interests.
We did the same thing when Google insisted on tracking our users or they would refuse to pay us. We put our users' privacy ahead of our financial interests and refused to allow Google to track you.
I personally know the business models and technical workings of many other so-called privacy services and I'll personally recommend one exercise great caution. I can not trust (with what I know about them individually) the vast majority of so-called privacy services.
Alok, Epic Privacy Browser Team