When comparing Tails vs Kubuntu, the Slant community recommends Tails for most people. In the question“What are the best Linux distributions for desktops?” Tails is ranked 19th while Kubuntu is ranked 30th.
Ranked in these QuestionsQuestion Ranking
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 Full featured desktop environment that is actively developed
Unlike some abandoned, unfinished distros, Kubuntu is up to date and offers a fully functional desktop environment that targets workstation users.
You can easily adjust the workspace to your needs.
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 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 You can't install it to a hard drive
Con Slow internet
Tails uses the TOR network and as a result the internet on your computer will be very slow.
Con Often unstable
There have been several bugs reported. Some of these bugs are: shutting down randomly, refusing to boot, refusing to shut down, menus may act strange, icons may disappear, etc...