RethinkDB sounds like it's document oriented from their site: "RethinkDB is built to store JSON documents, and scale to multiple machines with very little effort. It has a pleasant query language that supports really useful queries like table joins and group by, and is easy to setup and learn."

Also not sure why relational == Meh.

RthinkDB does sound promising though not ready for primetime. The following (critical) features are still in the development pipeline: Secondary indices, a db backup tool.