I think this is a classical case of "use the right tool for the right purpose". If you want to do "classic database" stuff, use a classic SQL database. But if e.g. graph traversal is a cruicial operation for your application, then looking at NoSQL solution seems to be quite interesting.
In other words: I wouldn't call a screw driver a bad tool, just because it's not as good at driving nails into wood as a hammer.