Active since 2004, independently developed, and now a rolling release. An early Gnome 3 and systemd adopter, with largely vanilla packages, and a number of customized install metapackages.
The mono-based package manager is command line only and slower than apt-get, etc, but it works fine with the basic upkg-install/remove/upgrade commands used with packages from the online repository. The packages repo is sufficient and has been consistently maintained for years.
The developer is responsive to inquiries but there is no real community. Basically, paldo is the personal project of a software professional and available for intermediate or advanced users interested in a current distro with some unique bits and not based on the usual debian/red hat/opensuse projects.