This is a must have for Drum & Bass producers... especially for neurofunk... the fact that it's free is insane! Sounds great on basses with a huge helping of distortion! The only thing I would add be an option for it to automatically disable the filter when it reaches 0 for highpass or 100 for lowpass for some drum filter sweeps. You can accomplish the same thing by automating the bypass setting in your daw.
I did encounter a bug when I deleted the plugin from a chain in Reason 10 and it crashed the plugin instead of deleting it. The other plugin instance kept working though.
The HP / LF Filters work fine, resonance control allows a more interesting tone shaping, but the big surprise for me was the drive control. Usually - as a guitarist - I often are not too convinced of a lot of not especially for guitar designed gear, which offers digital audio saturation, overdrive or distortion, nevertheless I'm always curious about new gear.
Quite the opposite here. Adjusted properly you can use this plugin as well as a small, easily adjustable and very flexible overdrive replacement or even as an amp-sim replacement, if you are looking for some very well controllable transparent, naturally and harmonically sounding overdrive or distortion tones. I know some overdrive / distortion pedal sims and amp sims, which for me sounded worse than some of the tones, I got out of this small plugin at my first attempts, even without any IR-cabinet or additional other gear. With additional plugins it also works fine.
My experience was, that less often is more, especially when adjusting resonance and drive.
A very good and useful tool for a flexible sound shaping, while maintaining the sonic qualities of tones or even improving them.