While Scala's Akka is pretty sweet for concurrent systems, Erlang/Elixir puts them all to shame. I think that Elixir and Phoenix will very rapidly assume position #1 for web frameworks, surpassing Node.js and Golang among the cutting edge but practical crowd in the next 1-2 years, and surpassing Ruby and Python among the more conservative crowd in the next 3-4 years. Java may be so entrenched in Entreprise systems that it will never be replaced, but if any ecosystem could do it, it's Erlang/Elixir.<p>That said, if you want to work with one of these two languages in a job <i>now</i>, Scala is obviously a better bet. But I could see that changing in as soon as 1 year from now.<p>Also, if you plan to mix a lot of computationally expensive stuff with concurrency, then Scala may be worth seriously entertaining regardless of the job situation or popularity, although for that, C/++ and ZeroMQ may be the best bet. Based on my limited experience, and what I've read from expert Erlang users, hybrid C/Erlang projects tend to eliminate a lot of the concurrency benefits that pure Erlang systems have.<p>But I've been playing around more and more with Phoenix and other Elixir and Erlang projects over the past month, and am pretty amazed at what I've seen. As much as I enjoy FP, I'm sad that I discounted Erlang for so long because of its lack of static typing (which is unfortunate, but far from being a deal breaker for me now that I've explored Erlang a little more).