I use MariaDB in production. It was totally trivial to drop it in as a MySQL replacement and usually gets slightly better performance. Not to mention not relying on Oracle who one can imagine might not want to give MySQL as much love as it needs given their other database. So I can see why Redhat would want to do that.

As for the name, MySQL was named after Monty's daughter My. MariaDB was named after another daughter Maria (http://en.wikipedia.org/wiki/Michael_Widenius). I think its sort of sweet. Maybe someone has a kid called Postgre? ;-)