I've been using Elixir in production for four years now, in a fairly complex SaaS app, and I can comfortably say I've never had to "learn all the gotchas of BEA

I've been using Elixir in production for four years now, in a fairly complex SaaS app, and I can comfortably say I've never had to "learn all the gotchas of BEAM and OTP". IMO Elixir/Phoenix do a really good job of abstracting all of that away from you, while still making it easy enough to tap into their intricacies if needed (e.g. if you want to write a GenServer for something). Lack of library support was a bit annoying at first. But then I realized that, back when I used to take advantage of existing libraries in Ruby/Rails, in the vast majority of situations I was just utilizing a small portion of those libraries anyway. It ended up easy enough to write my own code for those features.