First you get a boost with a sweepable mid frequency eq.
This side of the pedal allows to boost any guitar/amp combination (strat bridge pickup into a plexi or a 335 into a blackface) in a very pleasing way. It can be sizzling or wooly. but never harsh. it could easily be an always-on effect, as it brings some sheen and color over the dry signal.
Then you have the overdrive side of the pedal.
Despite a very healthy amount of gain available on tap, you have direct access to all nuances by rolling down the volume. From colored cleans up to max gain, the pedal remains very dynamic. Although it does compress the overall volume, the nuances of the pick attack are translated into nuances of distortion. This allows for great expressivity, despite potentially being in high gain territory.
The character of the overdrive, while raw and potentially agressive, remains creamy. it can be made woolier and/or sizzling, but is never harsh. I was able to find usable settings with 5 different amps and 5 different guitar combinations. from blues to rock, to harder rock. Always musical, with an amp-like bloom on single notes. also respectful of the guitar you plug it in.
Then you can combine both sides and switch their order. It opens up a new level of possibilities. From extreme EQing to solo boost, while maintaining the raw but smooth character of the pedal as well as its dynamics. Even with a tremendous amount of gain rolling down the volume control will eventually get you a nice clean colored and dynamic sound. With all the very musical in-betweens.
I have only one issue with the pedal: the Pre/post switch is for the overdrive side relative to the boost. not very intuitive at first.
I was looking for a higher gain overdrive to complement low gain overdrives/boosts into a JTM45 set to be clean at 7 on the guitar's volume. The range of tones accessible with the pedal in this configuration surpasses all the pedal combinations i have tried so far (ODR, TS, Klon, BB, Timmy, Boosts). more dynamics, less noise, more gain on tap, nicer clean-up. Very versatile !!