... about 8-10 years ago, that was the hottest thing since sliced bread in germany (where it´s made). I had one also, but not for very long. Back in the day, it was said it worked best with an accompanying pre-amp. I analyzed that preamp and all it did was cut out one frequency (can´t remember which), and maybe some impedance adjust- not sure. But the preamp could easily be replicated with a parametric eq.
The biggest downside to this pickup is IMO that it requires this enormous hole (ca. 8 mm) to be drilled into the bridge, and that is something that reminded me of the pickup years after I had switched to something else.
It´s kind of an ok pickup, if you like piezo sounds. But it´s nowhere near "natural" IMO. And most certainly it´s not like a microphone. There´s huge differences in the dynamics of piezos and mics, the ratio of attack vs. decay is completely different, not to speak of the piezo-tendency to have plastic-y highs, lots of finger-on-string-wipe-noise and no air at all.
If you´re brave enough to have this hole in your bridge, fine. (I´d rather leave the bridge totally untouched of anything, be it under the feet, in the wings, in a hole, whatever). I don´t know about today, but back then installing it meant sending the bridge to the maker so he drilled the hole and sent it back. Kinda clumsy.
Best
Sidecar