Bought this headphones for ~180$ and i'm very impressed with the sound. They are very easy to drive with my Xonar DG and even my smartphone allow me to listen to them with satisfying volume. Before them a had Sennheiser HD558 and always thought of their sound as detailed and airy but lacking bass for my taste. So i was worried that this beyer's will have muffled mids and treble cause of reviews of their cousin custom one pro. But Custom studio really impressed me with the level of detail and really clear treble. After listening to them for some time when i tried HD558 i was amazed how dark and muddy their sound actually is.
Overall bass response, level of detail and for my amazement even soundstage is much better than on HD558. Great headphones for 180$ (dunno why in the US their price is much higher).