Diminishing returns are real, but better sound quality isn't all you get with better headphones. Those Sonys I pictured above are incredibly well built, by hand in Japan. All structural parts of the headphone are metal - aluminum, titanium, stainless steel. The 'sliders' are aluminum and have precise clicking detents for each adjustment. The earpads are real sheepskin and filled with memory foam shaped to the contour of the head, the headband is the same sheepskin on the head side, tougher cowhide on top. They're as awesome to wear as they are to hear - no annoyances, no plasticky crackle noises, no microphonics, no structural weaknesses.