Unique plug that does... something... better than any other!
I've been using this for a month on all kinds of tracks - vocals, harmonicas, guitars, piano, B3, maracas, bongos - and I love it. But I have to admit I don't really understand how it works. It clearly adds harmonic content, and each of the knobs does something, so I just turn them until it sounds good. It can smooth out an overly "picky" acoustic guitar, add depth to the body resonance of a vocal (yes, seriously), and what it does on a drum kit submix is just amazing. Unlike many compression or "coloration" plugs this doesn't seem to degrade a well-recorded track at all. It actually enhances it. I'm addicted.
I haven't yet tried it on kick or bass only because I haven't liked harmonic-type plugins on those in the past.
My only complaint - a minor one - is the lack of explanation about what the X and Y axes represent on the graph. There's a vague analogy to "a curve display in a graphics program," but this ain't photography and I don't know what that means.