[nemetroid]

I used Erlang in some university courses, and once wrote a simple crud app in Elixir/Phoenix, so my experience is somewhat limited.

Erlang's syntax is unusual, but after grasping the concepts I always found the language logical and easy to understand. On the other hand, I haven't been able to get comfortable with Elixir. It's a significantly larger language, which comes with higher complexity (but also lets you write code at a higher level of abstraction). I often found myself only half-understanding the code I was writing (and I always make an effort to fully understand what I'm doing).

And personally I find the Elixir syntax to be among the most confusing and inconsistent (especially when compared to Erlang).

Nevertheless, if I was making something web related, I would definitely go for Elixir (because of Phoenix). If I was making something lower-level, I would probably consider both options.