It is end to end encrypted when you are one of the participants and you own the server. Thats what I mean by its the best secure communications solution I have - I can sholder the work of getting a valid cert, but once its setup as long as I trust who I'm talking to is who I think I'm talking to, I am sure nobody can evesdrop because its my server. And for the people I care to have private conservations with, downloading / install Mumble on their phone or desktop is their regular patterns of behavior and isn't inconvenient at all compared to insanity like GPG or OTR.