Although I bought and use Mach Desktop, and like it's easy of use and many nice features, I have to say that I'm very impressed with Screenwatcher. It took a little time to figure out the interface and see how to add and activate QT and Quartz compositions, but it wasn't hard to do. And I really like that I can create *categories" of movies and thus have playlists of videos I want to show on my desktop. I can't do this with Mach Desktop. Way cool, especially for a free app. Highly recommend Screenwatcher.