I wrote an article about how faster is Crystal compared to Ruby. I shared the performance difference and some code :)
https://medium.com/@voising/how-crystal-performs-compared-to-ruby-filtering-module-for-marketplace-3349277f5771?source=friends_link&sk=2a061131ff075ddbb4e4ee3706cffb40
Good info, just got done reading it. I haven't messed with either yet, so that will be helpful when deciding.