Elixir is terrific, never feel like the language is slowing me down whatsoever.
The tools you need are unsurprising and boringly in your face. Oban background jobs, auth, encryption, the works.
The tools for your day to day are polished and immediately useful. mix ecto.reset, seeds.exs, mix test, mix format, mix compile --force to see warnings. Just everything right there in your fingertips and works unsurprisingly.
Performance to the point where you won't ever really worry about it until you've made it big. Literally using 275MB right now and chilling. Sub 100ms response times.
All this to say, give Elixir and Phoenix a try. It's been the best decision of my professional career to try it out in 2016.