Does exactly what it's supposed to do and it does it well. Gives you that total transparent sidechaining compression. For example instead of increasing the vocals volume you let the vocals push back other instruments - but only on the common frequency. Or, the favourite: Insert it on a bass track and let the kickdrum control /push back the bass - only where the frequencies are common and only on the kickdrum beats. A good way to clean up low end in a mix.