https://mariadb.com/blog/mysql-56-vs-mariadb-100
So if you need, for instance, MySQL 5.6's partitioning improvements:
https://blogs.oracle.com/MySQL/entry/mysql_5_6_is_a
You're better off on Oracle MySQL. There's other tradeoffs, depending on what you use. What bugs the heck out of me is how a fair number of MariaDB advocates spread FUD about Oracle (if you judge them by their track record, they've committed to improving and maintaining MySQL -- they're not perfect, but that's no excuse to harp about stuff they COULD do when there's no evidence they WANT to sabotage MySQL to force you to switch to Oracle), and want to turn the debate into a holy war rather than focusing on letting everyone pick the best tool for the task.
> You're better off on Oracle MySQL.
Hardly true, given the two db's are mostly the same except that the creator is now making newer and better changes in the 10.x branch of MariaDB (Monty left Oracle just like most Sun employees due to inner-politics and fighting that is regular at Oracle).
I'm no DBA, but I'd think Monty (the creator of MySQL) and his smaller crew at his consulting firm (SkySQL and MariaDB Consulting) which makes MariaDB would be more open and flexible to working directly with Github's teams and needs than through the bureaucracy at Oracle.