Gauche is excellent for system programming but obscured by Guile.
I've been reading Gauche manual this morning, but couldn't find anything that made it have a distinctive advantage over Guile, at least in my eyes. And if there really is no technical advantage, Guile appears to have the upper hand is speed (https://ecraven.github.io/r7rs-benchmarks/, whatever that means) and in pervasiveness - because certain GNU utilities optionally depend on it (GDB, Make, ...), you won't have to install another Scheme implementation just to run a script.