Well just got this preamp as many others here have indicated, you can't find many reviews out there. So consider this one of them.
I also now own NHT's new flagship Xd system. This preamp is a perfect match from what I can see in the first day. My previous preamp, an excellent one by Space Tech Labs, the QA-808 was part of the previous system (B&W 803 Nautilus, McCormack DNA-2 Rev. A modded) and great for that.
But for this digital system, it's no contest. I didn't expect there would be much of a difference but there is a huge improvement in dynamics, soundstage with the PS Audio GCP-200.
As PS Audio also couples this with its own digital amp design, maybe I shouldn't be so surprised. As Xd has its own partner relationship for their digital amplification, it's a superb match.
This preamp can play very loud, up to 130db according to the manual, and there's no noise floor I can distinguish. Their gain technology application seems to do exactly what they said it would. It preserves the quality of the sound at all volumes with no distortion.
