Depends on the use case, but basically, there is a big set of problems you can solve with different technologies depending on your exact details, one will be better in one way, one will be better in some other way. The sensibility of the programmer is to pick the right one, in an effort to maximize the different aspects: data model fitness for the problem at hand, operational aspects, consistency guarantees, performances (number of nodes needed), scalability, simplicity (do I need support since it's a complex stuff?), and so forth.