The first item is the syntax, Go use braces while Crystal is Ruby based syntax.

Go has full parallelism support. Crystal is WIP.

Go has Windows support. Crystal is WIP.

Crystal and Go performance are very similar.

Go is backed by Google and his community since 2009.

Crystal is backed by Manas.tech and his community since 2012.

Go has full featured IDEs like https://www.jetbrains.com/go/

I hope to have Crystal IDE support after 1.0 :-)