FWIW, Kemmrich and I just traded headphones. I sent him the M50s and he sent me the M40s. We are both happy

I have a set of Sennheiser HD's here somewhere .. but I think they are the 200 series, not 800. I don't know where they are because I wasn't impressed at all. I think they are in my book bag for school.
Kemmrich seems to have a knowledge of Sennheiser 'phones, so hopefully he will chime in.
What's failing on the 7509's? Earpads (often easily replaced)? or cord? or ?