Node.js or Erlang

Question

I really like these tools when it comes to the concurrency level it can handle.

Erlang/OTP looks like much more stable solution but requires much more learning and a lot

Answer 1

It looks like Erlang performs better for deployment in a relatively low-end server (512MB 4-core 2.4GHz AMD VM). This is from SyncPad's experience of comparing Erlang vs Node.js implementations of their virtual whiteboard server application.