Mandriva has a reputation of being good for beginners, although it is a full featured distro. Mandriva aims to provide the latest applications and features. By comparison, some other distros (like Debian stable) take a more conservative approach, sticking with slightly older, more proven applications to give higher certainty of stability.
The UseNet newsgroup alt.os.linux.mandrake has an active support community for Mandriva.
Mandriva Club membership is optional, and has various levels (standard, silver, gold, platinum). Club membership gives access to expanded versions of distros, expert forums, club mirrors, etc. For many people, the main reason for club membership is to support ongoing development of the distro.
Originally known as Mandrake and founded in 1998, they changed the name in 2005 after buying Brazilian distribution Conectiva, thus settling a long-standing court case with the owners of the Mandrake The Magician trademark. Seems some American lawyers couldn't tell the difference between an old comic strip, a modern Linux distro, a plant and some other uses for that name.
Mandrake was originally forked from RedHatLinux to replace its default GNOME DesktopEnvironment with KDE. Since then, their paths have diverged substantially, with RedHat focusing on enterprise customers and Mandriva catering for both desktop and for server uses. While they're both RPM based, packages for one system will not always work on the other.