[1letterunixname]

Your own, hosted on a VPS in a non-US extradition country maintained by locals. Otherwise, you have no expectation of privacy or of durability, a-la Lavabit because a corporation in the reach of the US Gov can be squished and bullied whenever. That single company that runs an email service will always a SPoF. At least if you run your own on multiple machines on multiple providers and use a reputable domain registrar that can't be pushed around, you have HA.