On my iBook G3 this doesn't appear to work at all. The DivX player crashes upon launch, and I can't view any DivX movie in QT Player. I suppose nobody takes G3 users into consideration anymore.
This aside, I'm not particularly fond of the move towards a standalone player, unless everything is still based on a QuickTime plugin, so I can still open DivX movies in other QT based applications. It appears that this is the case (if it would work), because QuickTime plugins are still installed. So I suppose the DivX player is just another QT frontend without a ridiculous full screen restriction. So if you have a fairly recent Mac this might be good.