Pros
I liked the fact that RiskRecon was interested in switching all their code from Ruby and Python to Elixir.
Kontras
THE CODE!!! What a disaster! Things that should have been integers or Boolean fields in the database were TEXT fields (not varchar fields, but text). Things that should have been varchar were JSON strings with one key/value pair. The REST API was so slow (because of piss-poor database design) even other internal tools couldn’t use it and had to hit the database directly. In Elixir/Phoenix, their developers mixed schemas and contexts into the same file and then wrote code to work around the module errors that doing this causes. They hacked together Elixir/Phoenix code to attach to a Ruby on Rails app and insisted on running migrations from Ruby on Rails instead of the Elixir code for the sake of “finishing the project.” I worked for six months on a project that would have taken me a month to complete by myself, if we had just done it right the first time. In the end, I couldn’t take it anymore. It was just too frustrating to watch mistake after mistake being made by engineers with very little experience with Elixir and seeing those mistakes being supported by management, all the while the project was failing.