I just got this in from Luxman for test. So far, I have to say I really like it. The P200 drives the HD800s and Denon 5000s with ease and the sound is very pure but not etched. I have some other amps to try, and I don't have a wide basis for comparison, but this sounds like music.
I've had some time to compare the Luxman to the PS Audio GCHA, using the Sennheiser HD800s. The differences aren't huge so far, with both amps driving the HD800s comfortably. I'd say the Luxman is brighter and the PS Audio warmer by a small degree. Sibilants seem a little sharper on the Luxman. Whether because of this, or for other reasons, the PS Audio has a more relaxed sound, while the Luxman sounds a little more alive.
My feeling at this stage one can't really conclude which approach is right without including the headphone in the conversation. Headphones, like speakers, deviate from complete neutrality and I find the deviations of headphones at high frequencies to be the most noticeable part. This is the same area where amplifiers often deviate from perfection. Inevitably, you are listening to a combination of distortions and some will be synergistic and some not.
In the case of the HD800s, there seems to be a small lower treble depression. That makes a slightly brighter rendition of the sound, at least as executed by the Luxman, a welcome thing. Said conversely, it makes a warmer presentation pleasant but less accurate sounding.
Digital source, BTW, is the Esoteric DV-60 in PCM>DSD mode.