"With true Mac OS X feeling"? You're kidding, right? It looks like it should be multi-document-aware, but it isn't. It QUITS when closing a window. You have to enter a dialog box and set settings to even play or preview the sound. The whole interface is completely un-intuitive. The examples aren't exactly interesting. Check out Sound Builder instead, http://www.venus.dti.ne.jp/~khidaka/soundbuilder_en.html or http://www.versiontracker.com/dyn/moreinfo/macosx/15582 . The interface isn't more mac-ish, but at least you get some real and interesting results when tinkering with it.