ATROCIOUS DESIGN FLAWS: I remember, after using the HE90 for the first time, I removed the headphones from my head only to find little black particles near my ear and on my fingers. This was the result of the faux-leather used in constructing headband and earpads. I thought that there was something wrong with my pair, but I quickly learned that this was a typical occurrence with the Orpheus. How could Sennheiser design what was intended to be the world's most supreme flagship headphone and not use better materials than this? In some ways it does take away from the joy of owning an Orpheus. Every time one uses it, the quality of the headband deteriorates to some degree. If Sennheiser objects to using real leather for animal rights reasons, I fully respect this, but the materials used here are clearly cheap and inadequate. A third party would be wise to create a real leather replacement for this headphone. I remember that the manufacturer JMoney had proposed the idea of creating a leather headband replacement for the HE90, but I don't recall what came of this proposition.
EXTREMELY EXPENSIVE: To my knowledge, the HE90 and its required amplifier is the most expensive headphone system of all time. Depending on the condition, expect to pay somewhere between 7 and 11 grand for the headphone alone. If the amp and headphone are sold together, the asking price may be more than your car's. It is hard to put a price on something that is perceived by many as the best in the world. While I do perceive the sound quality of the HE90 to be the best in the world, I cannot justify the price and I do not recommend purchasing it. If you intend on purchasing the HE90, make sure you can accept that a well-driven HD800, LCD-3 or HE-6 (all currently in production) can get close to the resolution of the HE90 at an extreme fraction of the price.