But I'd bet both of them perform far better than MzScheme.

In any event, it's a "solved problem". The sheer amount of time and effort going into this is silly. Just pick a better language/platform and use it.

I guess the point is, axod, if you aren't willing to backup talk with action, it might be best to think about what you say before you say it.

Don't slam something saying I could do better, and then have your bluff called.

Makes you look silly. This applies to even if the person calling your bluff was NOT pg.

It depends on what you mean by "perform better". Any reference-counted GC mechanism will have memory leaks, which is a serious problem in a long-running process. Python gets around this by also occasionally running a traditional GC, which, btw, is a stop-the-world GC.