To be fair, and I find this to be a bit of a shame, but most of that robustness and ecosystem comes straight from Erlang, which was always solid. Though I do enjoy the consistency that Elixir brings and the improved macros. I'm a Clojure guy, so I also love the protocols.

Just wanted to say that Erlang vanilla is robust and has a great ecosystem. So Elixir builds itself on top of a solid foundation.