So I just played it for about an hour, here are my first thoughts...
This thing does EXACTLY what I wanted it to do and sounds EXACTLY like I wanted it to sound. Transparent to a T, and does an amazing job both attenuating my 100w beast and amping my 1w. It just sounds killer, even after an hour I don't know how I fared before it.
I've already phased my OD pedal off my board and quite possibly my volume pedal, as with the volume and gain in the sweet spot I get such natural, organic crunch with singing sustain, even better than my pedal. Makes it sound like a buzzsaw in comparison. Even with my gain levels at around say a GNR type sound, rolling back on my guitar's volume cleans it up beautifully. I didn't know this was possible before today.
All in all, this is a fantastic device. Anyone thinking of getting it, get it. You will not be disappointed.