Ticaga I always use MariaDB because I find it faster than MySQL (even though they are getting faster), it's developed by the some of the main developers who started MySQL which in my opinion is a great thing and it's a drop in replacement to MySQL.
Amadex My choice is MariaDB too. Never had any problems with it, so I'm using it mostly for WordPress.
Dan It depends on the project. Mostly Mongo and Postgres for custom/in-house applications, but when I need to use a ready-made application then it's MariaDB 95%+ of the time.
