I was a bit sceptical about the praise Elixir was getting, but after working with it for a while... I started noticing a lot of stuff that is lacking or abused in Ruby and Rails.
I think that Elixir is gonna catch up. If you write a project where you need to use a lot of external libraries probably Ruby is better. If you don't need to rely on the external dependencies too much and you want to/have to write your own code(libs), imo, Elixir is a better option. It also depends on a project, lots of external api calls, webhooks, real time chatrooms, etc. I think Elixir is gonna be a better option.
One thing more, because Elixir's code is much easier to deal with, it's easier to fork and fix deprecated lib than in Ruby(Rails).
It's just my opinion.
Of course, the quality disparity exists in part because there is a much wider pool of developers with varying levels of experience in Ruby, similar to Node.js. But I believe Elixir encourages and even enforces a certain level of code quality, without introducing fragile mutable state, security issues, and package incompatibilities. Thus I expect the quality of Elixir libraries will remain high even as the pool of Elixir developers grows.