I can't speak for everyone, but I recently started on a project I chose RethinkDB for because of the support for joins. It's very nice to store documents, but i

I can't speak for everyone, but I recently started on a project I chose RethinkDB for because of the support for joins. It's very nice to store documents, but it's a pain to have to resort to an SQL database every time you have relational data, or digress and issue multiple queries to patch in your relations. Just basic join support allows you to have both documents and relational data in the same database, made the sell for me anyway.