Use this plugin all the time! It provides some awesome saturation models to choose from; it can add some smooth warmth, or completely mangle your sounds depending on the settings. It was such a great deal, and is a great alternative to Soundtoys decapitator if you dont wanna pay the big price tag sound toys asks for that plugin.
Probably one of the most useful saturation plugins around for enhancing and rebalancing individual sources.
I did a few A/B's with this plugin, focused particularly on a comparison with industry standard Soundtoys Decapitator, and was surprised to be able to reach very similar tone. Decapitator gives a bit more low end presence, but considering this plugin is around a third of the price (not to mention the excellent price drops during sales), the results you can achieve are amazing here, and you can compensate by using a unit that generates low end-specific saturation along with it.
Use it as an exciter, after a slow attack compressor, a preamp, a channel strip for mixing into, or even as a distortion unit.