Having used Mandriva (and Mandrake before it) ever since Redhat split its distributions I tried the 2011 version... It was a complete pig's ear of a release, especially if you want to integrate it into a shared network or use it for real work. The worst part (other than systemd and its intrinsic brokenness) is the default "Start" menu replacement. (Oh, and the WiFi is completely broken, the wired networking half so.)
Mandriva 2010.x was stable and worked very well and this is the basis for Mageia.
If there were anything they should kill it would be the "desktop" version, start with the old code and move forward.
As to the anonymous coward who wrote the essay on how bad Mandrake/Mandriva is, I'd just show him URPM, the distro installer (for 2010.x) and compare them with the other distros' solutions. They pale beside them.