It all depends. When you're talking about MySQL, do you mean MySQL 5.5 (the penultimate and most stable version) or the brand new Oracle released 5.6? If you'

It all depends. When you're talking about MySQL, do you mean MySQL 5.5 (the penultimate and most stable version) or the brand new Oracle released 5.6? If you're not one to jump on the 5.6 bandwagon there isn't a lot of difference between MariaDB, XtraDB (Percona) and MySQL 5.5. To make it even more confusing, MariaDB includes Percona's XtraDB (a patched InnoDB) so in essence with MariaDB you're also getting Percona, although perhaps not the latest offerings from Percona. Oracle MySQL 5.6 has a number of interesting new features and performance improvements that I don't believe have yet made it into either XtraDB or MariaDB. So if you're talking about MySQL 5.5, MariaDB and XtraDB are really drop in replacements, they're all based on the same codebase, and hardly anything differs except the InnoDB engine. MariaDB and XtraDB have as few experimental InnoDB bug-fixes and performance tweaks that vanilla 5.5 does not.