Using Erlang vs Node on my current project was a serious consideration. It is well thought out and its message passing and lightweight process based design is more evolved than anything node has or likely will have. It's also Erlang and I have found productively programming in it to be incomprehensible. Maybe its a personal problem, but it is what it is. Ditto for Haskell. I was surprised to find that my brain didn't bend that way.