I'll stick with MySQL, the features and stability just keep getting better. Replication, Memcache Plugin (with amazing write and read performance that supports replication), InnoDB Barracuda compression, JSON datatypes (in 5.7), it has scaled amazing well for us at Enginuity Search Engine. I should do a write up on our company blog sometime about all this.
Sounds more like "I'll stick with MySQL because it's what I know" than any kind of a holistic comparison between the two.