If you haven't guessed/realized by now, yes, this is a tube screamer variant. The proverbial cat being out of the bag, on to my thoughts...
I have sampled many a fancy screamer, but this one rises to the top. While you certainly get the airy/singy midrange (it's thick and pronounced but not overbearing in most cases), you also get a very full low end and an extra smooth high end. My favorite aspect of this circuit, however, is that the typical 'clean blend' texture that nearly all TS's and their ilk exhibit when played on a CLEAN channel is nearly non-existent. Pick attack is not stifled and while there is some mild compression it cleans up with a volume knob as well as or better than anything out there. My only complaint is that I wasn't able to get one in the purple finish (mine is 808 green, but it's #28 and signed by Mr. Keeley).
Is this pedal breaking any new ground? Not really. But it feels/plays like a very refined and completed idea that makes me smile and want to play more.