[abannin]

When clients ask this question, I always suggest starting with a good SQL solution and then figure out why it won't work. So if you're not hitting any major problems with MySQL or SQL Server, then NoSQL solutions will just be incredibly labor intensive for, from your perspective, a loss in functionality. Each NoSQL database is different and designed to approach problems from SQL databases differently. For Mongo, this is having a very flexible denormalized schema with very fast reads. However, companies such as Pinterest and Facebook have found they can accomplish this with MySQL or Postgres through different data modeling. I think the reasons for NoSQL become much clearer when trying to build applications that do not keep a normalized data model.