Lucky core dev here! I've been using Crystal in production since about 2017. I love the language, but there's definitely some hard tradeoffs which are mentioned in this thread. Our larger app has some serious compile time issues. We deploy with github actions, and it takes about 30min to build the production binary, compile assets, and push the binary to the server. But overall, I've found my apps are way more stable, and really fast as well as running on much smaller machines. The tradeoffs for us are definitely worth it.