MongoDB is really, really bad. I&#x27;ve never come across another product that was so horrible and yet so widely used.<p>MongoDB: for when you don&#x27;t need consistency, availability, <i>or</i> partition tolerance.<p>There are some really good NoSQL products out there. I seriously think RethinkDB is on par with Postgres. I&#x27;ve also used Cassandra and BerkeleyDB and they&#x27;re both decent. But unless some core part of your business logic is pathological to implement in SQL (like Reddit&#x27;s comment trees) you should go with Postgres.