After 15 years as a Ruby developer I decided to start two new projects with Crystal and there is no regret. The only thing I can say is that working on Ruby projects is a lot harder now. I am hooked to Crystal’s type safety, while I used to hate it on other languages.

I think you forgot to mention another framework that is gaining a lot of traction: https://luckyframework.org. It solves many issues I had in Rails. Like better separation of concerns and easier testing. Of all Crystal frameworks, it offers the most complete feature set.