ActiveRecord is more pleasant to work with than the ORM of Phoenix IMHO, but not everyone shares the same feeling.
Despite having built in concurrency my team ended up building a version of Sidekiq because supervisors don't cover all use cases of job control.
I prefer deploying with Capistrano than with Elixir builds. Another matter of taste.
Structural pattern matching is the only feature I dearly miss, but that's a feature of the language.
We never used Liveview. We had a backend for a JSON API so I can't compare that feature.