Anyway, NoSQL is definitely a good solution for some usages, I personally created a special analytics service using Cassandra that is good to store unstructured and unrelated data to be later computed and analyzed. It would be barely impossible to achieve this without hitting on performances due to the data integrity checks that most SQL servers/engines perform. On the other hand, I use SQL everywhere else and I am happy with that. It scales well if the design is well made and it's just a matter of research and a little bit of preparation to create an SQL environment that scales. It's not easy as some NoSQL databases, but not that hard and impossible as some of these solutions are claiming to gain new customers...

On Node.js I have some doubts, even if the general nature is very scalable and is well proved as fact, there are other solutions that are good alternatives like Golang or some frameworks written in Scala, maybe on top of AKKA.

The big problem is that a lot of companies and investors are asking for scalability, but the reality is just that one service on hundreds built are going to be so successful to require a scalability plan. If you hit that target you would definitely get enough money to even migrate the technology to something better and scalable.