Congratulations to the team, Chicken Scheme is a little gem!
I was slightly worried that I'd start using v5 and then v6 would come out but it looked like they'd been working on it for a while so I figured I'd have some time on v5. Turns out I was wrong!
CHICKEN is a compiler that translates Scheme source files into C, which in turn can be fed to a C compiler to generate a standalone executable. An interpreter is also available and can be used as a scripting environment or for testing programs before compilation.
It has good emacs support with geiser-chicken.
Because it compiles down to C the FFI provides a lot of nice ergonomics beyond what I get with Chez Scheme.
Error messages are actually useful with a stacktrace. Can't overstate this.
It supports optional type definitions which reduces the number of tests I need.
The docs are adequate, though I frequently add "MIT scheme" to my search queries. I wasn't able to get chicken-doc setup in NixOS, and the docs website has gone down on me a bunch lately. I wish Chicken had complete documentation available including its eggs in an offline format, like a PDF.
The generated C is reasonably portable, so you can run Scheme programs on systems that “don’t run Scheme”.
But then Scheme was always less EVAL-friendly of the lisps