Well, this is one hell of a free tool to use. Frequency Modulation and Ring Modulation and Amplitude Modulation. Very nice results come out of this. GUI is a bit confusing at first but is simple once you tweak on the knobs enough to figure out what you are pressing. It isn't gaudy. I haven't checked the documentation on it so I can't really comment on the documentation. The presets are more helpful in understanding in what it can do, rather than the actual use in your works. I haven't come across any crashing or anything along those lines.
All round a very cool tool to have and use especially in the more noisier genres such as metal or gabber and terrorcore.