I can't speak for the sennheiser, but I've been using the same ath-ad700 for close to three years, and I love them. Very comfortable, my ears have never ached, like what happens with many others I've tried.
The cord is also extremely durable, I can't count the number of times that I've rolled over the cord with my chair, or been sitting on the cord with my chair and pick up the headphones, only to have them just about yanked out of my hand by the taut cord. I'm surprised I haven't had a lick of trouble, definitely beats annually purchasing a microsoft/logitech headset only to have it break after a year. My GF also loves them because they are purple. I hadn't even considered that they were purple when I bought them, I was just so happy with the reviews I had read. I don't find that the colour detracts from them at all.