[jdhendrickson]

The replication you get when you combine it with Galera. If postgresql had that I would drop mariadb, but the painless replication and having multiple read write masters is too good to pass up on. Conversely if Mariadb would add the json data types that postgresql has I would probably never think about moving.

[e12e]

For those, like me, that hadn't heard of Galera before, it's a library that ships with(?) mariadb, and is also being developed for postgresql (no release date). Fully open source, and at least on paper, looks great (I have no experience with it):

http://codership.com/products/galera_replication

http://codership.com/products/postgresql_galera