I got the parts express headband, but still prefer the ear clips, they're extremely well-engineered and never cause discomfort, even after several hours.
The bass is just about perfect, there is maybe a small amount of distortion, but its actually super enjoyable. The grill has four 5/32'' holes around the edges to increase bass output, and the bass is very dynamic and forward. One surprise is the bass reaches
down to around 60hz, adds a nice bit of reverb to the sound. These 75's can go extremely loud with zero glare or sibilance, Koss did a great job engineering the driver.
The stock foam pads are pretty nice as well, no desire to try the PX200 pads as some on this thread have said they mud the sound up.