Of course the Crystal people probably don't have the same number of developers working on it as Go did even early on.
Edit: Go took a little while to support windows, not until around July 2010. See this question from November 2009: http://stackoverflow.com/questions/1717652/can-go-compiler-b...
It does exist unlike Crystal, so you should explain what you mean by poor. I never had a problem compiling a project with CGo on Windows.
The way they interact with different types, fibers and allocation on the stack vs heap, etc. Makes sense?
Edit: To give you an example of how friendly the Crystal lang & API documentation is to developers unfamilliar with the language, let's look at the Iterator: https://crystal-lang.org/api/0.18.7/Iterator.html
It comes with a great "introduction" to what it is, what it does and gives an example of the advantages it has over the Enumerable. It also explains how you can implement your own Iterator.
We can also look at the IO module for Crystal and the io package for Go: https://crystal-lang.org/api/0.18.7/IO.html https://golang.org/pkg/io/
From a beginners standpoint, you have to see that the Crystal documentation is way more friendlier.
I had never worked with compiled languages before I tried Crystal, but had always had a huge interest in getting into that. When I wanted to learn the compiled ecosystem I looked at languages like Go and Rust, but the learning curve for those was a bit overwhelming for a newbie. A while later I found Crystal, and much thanks to the simple syntax of the language I learned a ton of new things about compiled languages very quickly. The absolutely best part of the language is that it is written in plain Crystal, and I've been looking at their own implementations for various things a lot - something I've never done before, having worked mostly with Node, Lua and PHP before.
Nowadays I can delve into Go documentation, packages are clear to me and I just understand how things should and should not be implemented to achieve a good efficiency and performance level. The Little Go Book makes sense, the I/O package is simple and this is probably all thanks to the syntax of Crystal, the amazing language & standard library documentation but most importantly the source of Crystal being written in Crystal.
I'm currently working on building a business using Go, because I absolutely need Windows target support - something which Crystal does not yet have. But the second it gets that, I'm moving back. Don't get me wrong, Go is really great and nice to work with - but Crystal is my mentor. Please note that I have not worked with Ruby before, so the whole language was new to me.
To summarize; even if you only wish to learn, Crystal is in my personal opinion the best choice to go with.