[yeukhon]

Yes. It does bite you quickly. As you add more models you start to duplicate a lot more information and by that time you'd think relational makes sense but you have to continue to use MongoDB. The option you got is either embed or reference. And still, there is no JOIN in mongo so you'd iterate many collections and do combine within your application code.

I think as PostgreSQL continue to improve its JSON data type people will look at SQL again even if they need to a basic model working. Because at the end working with constraints can help. Well, either side will bite you but one has to weigh...and sure that's a tough question.