I used it sometimes when I needed a live Linux, and I liked it, because it used to be based in Slackware, and it had KDE as its desktop. Now they added Debian as another base, and that's great. Sadly, they dropped KDE.

There's also Porteus, also a Slackware derivative offering KDE Plasma -- https://www.porteus.org

Slax was and still is a great live distribution. The fact that (at least one of its flavors) is based on Slackware shows that the parent distro (Slackware) isn't that hard to use, something that few people believe. Slackware is in fact very simple in comparison to other distros.