If you still really want or need mysql please do check out mariadb, even old versions like mariadb 5.3 onwards added a lot of features and fixes for old problems from before the Sun acquisition (Remember, MariaDB was forked with the Sun buyout or MySQL AB, not Oracle). It's not entirely a drop in replacement though, read the manual and test your configs!
What MariaDB/MySQL is still really good at, is scaling horizontally pretty quickly, just be sure to separate out different schema workloads into different server instances, and don't make your schema overly complex. Not that it can get too complex anyway with SQL/PSM heh-snort snort.
Want to scale bigger and faster, and maybe with an even more highly tuned dataset per-cluster? Cassandra. Lots of Oracle and IBM business is being slurped up by Cassandra and Datastax.
Want mixed database workloads and all the RDBMS management, SQL and PL goodies? PostgreSQL.