I switch 3 machines from mandriva to mageia, using partitions already dedicated to mandriva without formating home partitions. I used three different CDs i586, live Cd and the x86-64. Al the three machines run now under Mageia. There has been no particular problems other than those linked to the use of nvidia proprietary drivers and flashplayer on the 64 bit machine. Curiously on the three machines aspell rpms were not installed.
In conclusion very good job of the team Mageia.
SM