Both solve entirely different classes of problem. There are functional overlaps for small problem domains, but as your infrastructure tries to do more, you may

Both solve entirely different classes of problem. There are functional overlaps for small problem domains, but as your infrastructure tries to do more, you may find a need to run several distinct lightweight services backed by a variety of datastores serving focused requests. Many of you have already seen Kovacs' comparison of nosql stores. Just throw a SQL DBMS into the decision matrix. Consider how several might work together. http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-vs-redis http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-vs-redis Fowler's microservice post is a decent introduction to the microservice architecture, which is more or less what I'm describing. http://martinfowler.com/articles/microservices.html http://martinfowler.com/articles/microservices.html Granted, this probably isn't how to get the MVP out the door. But once you grow, this architecture can prevent the formation of monoliths of pain.