RethinkDB is a topic that I had been investing some time into, because I tried to figure out which DB to use for cosmowiki. What convinced me about: it is a DB which offers the best of both worlds, the NoSQL world (schema "freedom") and SQL DB's relational data. RethinkDB has joins built-in as one of the core features. Besides built-in joins it claims to have a very simple scale out mechanism and almost magic, transparent fail-over since version 2.1.
Other RethinkDB links
- Importing your data
- Third-party administration tools
- a very simple admin tool for rethinkdb that I used
- unfortunately there seem not many community events (listed here)
- Thirty-second quickstart with RethinkDB