The argument about "same language on client and server" doesn't hold for me. For one thing, client and server share only a small part of the overall functional

The argument about "same language on client and server" doesn't hold for me. For one thing, client and server share only a small part of the overall functionality. Usually the database interfacing on the server and the user interfacing on the client will require substantially different code. For another point, Python, Ruby and even PHP come with a lot of available packages and libraries. Node.js has lots of them too, but generally I prefer Django's API design to be more pleasant to work with than node.js