MariaDB appears to be a direct replacement for MySQL and with additional enhancements and fixes.

For almost a week, I’ve made some performance tests using both an XP 32-bit and Windows 8 64-bit utilizing the MyISAM ENGINE.  The versions I considered were MySQL 5.1, 5.5, 5.6 and MariaDB 5.5,10.0.

NOTE:  My "Test" DATA consisted of 20 Million ROWs averaging 157 characters per ROW in one DATABASE of 100 properly indexed MyISAM-TABLEs.