With this plug-in, you can turn cheapo speakers or headphones into professional sounding equipment. The only catch is that you either need to know a bit about what all the settings do and how you can use them to overcome the specific weaknesses of your equipment. So don't expect instant magic, but the presets can help you to get started. Of course there are limits to what this thing can do, I can make the speakers of my iBook sound better but there's no way of making them sound like studio monitors :)

The only drawback is that this plug-in consumes a massive amount of CPU cycles, and it has gotten worse since previous versions. On my old 800MHz G3, iTunes' CPU usage jumps from 10% to 50% when OSS 3D is active (an older version 'only' used 38%). The developers say that this can be caused by the 'about' window, but during my test only the minimized iTunes window was visible. The weird thing is that I find reviews from G5 users with much faster machines, who also report 30% or more CPU usage. Clearly there is some room for optimization here...