I read things to this effect in the internet, but then you have more than one Scheme system that runs (or is able to run) on top of the JVM - effectively making

I read things to this effect in the internet, but then you have more than one Scheme system that runs (or is able to run) on top of the JVM - effectively making this problem disappear. So, I guess I am looking for other differences, things that are essential to the languages - not just differences in libraries...