Sort of a nonsensical premise, the three highlighted distributions have entirely different goals (use Tor, penetration testing, and security through VM isolation), but it does give minimal overviews of each, plus mentions a few more in passing. Worth it if you aren't familiar with each, or one that matches your possible interests.<p>Side note: Qubes, or perhaps the woman developing it, is sort of scary. I was reading ... her blog, I think, where the discussion had turned to the open sourcing of a provably secure microkernel. Alas, that's only with an embedded ARM system, they didn't even a try a serious proof with x86.<p>And for good reason, besides covering how difficult this was in principle (e.g. chipsets, IOMMUs), she mentioned finding a remote execution exploit that never touches your OS, it compromised a network card and rewrote its EEPROM, then on the next boot exploited a secure boot "feature". Kinda makes you despair about the current state of security :-(.