I am/was a huge Ruby fanboy, and I used Rails a lot and loved it (though had some criticisms around too much "magic"). I made the jump to Elixir/Phoenix around 8 years ago, and have loved it. Phoenix to me basically "fixed" all the things I didn't like about Rails (basically opacity and hard-to-find-where-it's-happening stuff due to someone metaprogramming aggressively). I will admit that I've been a functional programming fan for a very long time too. I always write my ruby code in a functional style unless there's a good reason not to (which is increasingly rare).

I still love and use ruby a ton for scripting, and still reach for Sinatra for super simple server needs, but Phoenix is my go-to stack these days.

I've also found the Elixir community to be amazing in the same ways the Ruby community is/was. It's not all roses, for example there's not as many libraries out there. Distribution is also not awesome so for example I currently use ruby or rust when writing CLIs. But for anything distributed (especially web) Phoenix is amazing.

This is a self plug, but I did a conference talk introducing Ruby veterans to Elixir/Phoenix some years ago. It's probably aged a bit, but should still be pretty accurate. https://www.youtube.com/watch?v=uPWMBDTPMkQ

The original conference talk is here (https://www.youtube.com/watch?v=sSoz7q37KGE), though the made-for-youtube version above is better because it's slightly updated, and I didn't run out of time :-)