Ranked in these QuestionsQuestion Ranking
Pro Truly open development community
All development decisions for MariaDB can be reviewed and debated on a public mailing list or in the public bug tracker. Contributing to MariaDB is easy and the patch flow is fully transparent and public. But it's not all about the code contribution either - MariaDB also has very active documentation efforts and other related things that help developers in their day-to-day database administration.
Pro Dynamic column support
MariaDB has dynamic column support which allows for some NoSQL type functionality. So one database interface can provide both SQL and NoSQL for different software development needs.
Pro More cutting edge features
e.g. GIS since 5.3