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.
But then Scheme was always less EVAL-friendly of the lisps
Congratulations to the team, Chicken Scheme is a little gem!
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”.
SBCL is not compact and its "image" concept is not universally liked by everyone.
Guile and Racket are not fast (nor compact).
Chez Scheme is not "ready to use".
You have no way to run Hypergiant under Guile. In Common Lisp, tons of packages for QuickLisp/UltraLisp will run on SBCL, CCL and ECL with ease.
In the end Scheme+Dependencies can be more convoluted than a subset of Common Lisp (you can avoid CLOS if you don't need it for instance).