This plugin is a good sounding unit. Unfortunately, the effect is at his best when the high CPU is on. And it's very heavy on it. Good for a small session but if you have a large project it's unlikely that you will have it on. For free, it's the best sounding tube saturation unit I've tested and the equalizer make it a lot versatile and the saturation is warm and doesn't sound fuzzy or digital.
99% of "circuitry modelling" is promotional snake oil for a company to sex-up their conventional DSP plug-ins. It's easy to tell this isn't the case here, as this is one of the best tube simulations I've ever tried.
The proper circuit model brings my machine to a screeching halt, but the hybrid model is still very good - often I'll produce under hybrid, and then render under the model. This is an addictive "mojo" plug-in. Few others compare.