I am aware that this in an old thread, but I am new to the site. The Koss Pro4aa are not the best cans I have ever heard, nor are they the worst. However, I chose them as my avatar because they hold a special place in my heart, and my ears. I was an on-air personality between the ages of 19 to 24 and one of the older dj's turned me on to them. At the time, I had used several cheap headphones ranging from about $15 to $45. The sound was not great, but it got the job done. What did not cut it for me was the wear and tear and eventual breaking every couple of months from these cheaper headphones. At the station that I was hired at was this old timer that had been on radio longer than I had been alive, and he used these huge, and what looked like aviation styled headphones. I fell in love with the retro look. He offered me a pair for $80, and I said sure, later I realized that I had probably bought a refurbished pair. (although all parts of the headphones appeared new, they were not in any commercial packaging) I used those Koss Pro4aa for the rest of my radio career and attribute my love of headphones to them.
I still have them and use them once and a while, when I'm feeling nostalgic. While they do weight a hefty amount I don't think I personally ever got tired of wearing them in the studio for long periods of time. I have a big head, size 8 in caps and hats, and have never felt that vice like clamping that some of you have described. I actually really liked the seal that they provided, because I never got any feedback from bleeding into a live mic. I will not delve into an actual analysis of the sound of these cans, but I will say that they were enjoyable to listen to with the types of music that we played at the station as well as my personal taste in music. Durability and retro styling are what made them my day to day choice for broadcasting.