I think it depends a bit on the purpose. If your goal is to learn a new framework and get a job, I believe Rails would be the best option, since there is a hug

I think it depends a bit on the purpose. If your goal is to learn a new framework and get a job, I believe Rails would be the best option, since there is a huge number of jobs available for Rails developers. Of course you can still get a job with Elixir and Phoenix, but not as many as compared to Rails ones. If your goal is to learn a new web framework and maybe use it to play with personal projects, then both Rails and Phoenix would be great options. Keep in mind that you can also learn both frameworks and benefit even more.