A high level and theoretic NoSQL debate doesn't help. We know all the strengths and limitations of both SQL and NoSQL. And we know when to use what. Moreover,

A high level and theoretic NoSQL debate doesn't help. We know all the strengths and limitations of both SQL and NoSQL. And we know when to use what. Moreover, NoSQL does not equal NoSQL—there're so huge differences between a Mongo, a Riak and a Couch. And there's much more than that beyond SQL (graph based DB etc.). What matters: The experience. I used MongoDB with Node one or two weeks ago for this first time and I was really impressed when I got it. There are many uses case where I wouldn't employ NoSQL or Mongo but there're as many where I would go w/ Mongo when usually relied on SQL. Why: working completely without schemes and even migrations is awesome. Just save a record in Node/Mongo with the native interface and the system is setting up the respective table and even DB in the same moment if not existant. Schemeless is not always the way to go but if you want to prototype or to get quickly out of the door, it's an mind-blowing experience (and it's enough for many web projects). And with the JS interface it's just incredible and totally different to other NoSQL counterparts.