i've started using Elixir for all my side projects. It's very satisfying to use and as it sits on Erlang/OTP, you get all the power of Erlang, all the libraries, etc. It still means it's not great for math; it's too slow just like Erlang. But it has all the concurrency and stability of Erlang/OTP in a new, sexy, non-prolog language.

Further, Jose Valim (the language creator) is incredibly talented as a developer and has made rapid progress in iterating the language, and responds quickly to suggestions. The mailing list is also picking up momentum, folks are contributing ideas for how to make the language great.

Yuri (yrashk) has spearheaded the efforts around a package manager - http://expm.co/ which allows all Erlang Rebar packages plus Elixir packages. Still missing is "binary" package support but that's been a gripe about Erlang for a long time.

I believe in Erlang/OTP and I really believe Elixir has a bright future. In a few years there will be folks who build Elixir apps and don't bother to learn Erlang. This could really freak out the Erlang "old guard" - many are friends of mine - but they don't really care that much, as Erlang has has always been a niche musical instrument and Elixir is Erlang's ticket to Carnegie Hall.