The Yamaha headset sits around my ears, the Koss on top of them. The Yamaha grabs my (big) head fairly lightly, but the Koss was a head clamp. The Koss headset was immediately uncomfortable, then I gave it another try and it was still uncomfortable. It smashed my ears painfully against my head.
Here is a photo of the ear cups on the two headsets, face to face (ear to ear?), with the Yamaha on the right. You can see that the Yamaha is clearly bigger.
Here are the two ear cups side by side, with the Yamaha again on the right.
Also, my CM500 would have lasted longer than seven years, but I tried to replace the ear pads and broke a wire inside the ear cup. I tried to fix that, but I soldered it three times and broke it four times, then there wasn’t enough wire left to solder.