I don't know... I'm not a marketing guy, but I think you could still find a way to play up the high quality of your security without looking a bit... "fringe". The "truly paranoid" bit isn't so bad if you combine it with a different second phrase. However, something else might be even better at evoking a "yeah, I need that" response in more people. To me there's also a bit of contrast: in my mind, the "truly paranoid" aren't going to trust anyone else to do their backups anyway.
