> Erlang can make sense sometimes, but it's probably not(!) comparable to Rails in those cases.

I have no dog in this fight, but I've seen many people say that -despite the newness of the library "ecosystem"- they get an awful lot done with Elixir/Phoenix, and have a lot of fun doing it.

(Remember that Elixir is -like Erlang- a BEAM language. This means that Elixir gets the ease-of-understanding and interesting features of its syntax and has access to all Erlang software ever written. Similarly, any and all Elixir code can be called from Erlang with little trouble.)

Edit: (Also remember that the BEAM equivalent of Ruby is Elixir, and the (most popular?) BEAM equivalent of Rails is (AIUI) Phoenix. Phoenix uses Cowboy as its HTTP(S)/SPDY server.)