Pros: Warmth, Clarity & Spontaneity
The Orpheus sounds fantastic. It is full of detail and clarity with a very flat frequency response. It also caresses the music, in that the music's presentation is very warm. The soundstage is excellent and instrumental timbre is very well replicated. These are my subjective listening experiences.
However, I believe the money would be better spent on speakers. I own a pair of Focal speakers that outperform the Orpheus at two thirds of the price.
In a blind test which I performed on ten fellow classical musicians, which included the HD800, HD650 and LCD-3, the Orpheus did not outperform these counterparts to a significant level. In fact, a lot of them preferred the LCD-3 and HD650 over the Orpheus and the HD800. After the blind tests, I revealed all the headphones (the participants were blindfolded at first) and asked them to try these models again. As expected, the Orpheus gained unanimous approval after the visual stimuli.
These experiences show that the high-end headphones often have negligible difference in sound quality; and that these differences get wildly blown out of proportion when visual stimuli is present.
All in all, the Orpheus sounds great, but does it really trump the other high-end headphones at a comparatively cheaper price range (around the HD800 level)? I believe the answer is a definite no.
As people have kept on asking, (I used the Beyerdynamic A1 as the amp). Used several power amps as well coupled with ESP100 adaptor just to see how it would turn out. (Most of these gear belong to my father, and it was done ad-hoc).