When comparing RetroPie vs Tails, the Slant community recommends Tails for most people. In the question“What are the best Debian-based Linux distributions?” Tails is ranked 31st while RetroPie is ranked 37th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Privacy focused
Pro Has TOR built-in
Use the Internet anonymously and circumvent censorship; all connections to the Internet are forced to go through the Tor network.
Pro Easy to use with an USB key
Cons
Con Not for daily use
Tails is a privacy focused Linux distro. The updates that you will receive are only for improving privacy and not for improving user experience.
Con You can't install it to a hard drive
Con Saved states are not present for security
For security reasons, saved states are not supported in Tails. Files can be stored in a separate, persistent volume which must be accessed with a root password. Personal settings (e.g. -- keyboard layout, window settings, etc.) are not saved persistently across reboots. This can be a hindrance for anyone not using English as their language, or not using a QWERTY keyboard layout.
Con Only GNOME desktop environment
Con Slow internet
Tails uses the TOR network and as a result the internet on your computer will be very slow.