It's simple for me. If I can't wear it without having to think about how it's bothering me, I don't want it.
I LOVED the LCD2 (basically the best sound I've heard for my taste, after the D7000), and I HAD to sell it. The discomfort was always a factor, even the vegan version with foam headband swap.
I demoed the LCD2 a couple months ago from Cable Company. Really fell in love with their sound signature, but nothing I could do would give relief from their clamping force and leather earpads that were very stiff. Tried stretching them out over several days using some thick books. My wife tried them on and had this extremely pained look on her face. She couldn't wear them for more than a couple minutes and said that if I bought them, for sure she wouldn't ever use them, and couldn't understand how one would spend that kind of money and settle for that level of discomfort (obviously she is not an audiophile. ) I still think about them, though.
Comfort wise, very happy with my Paradox. I have not read too much about how the Paradox compares with the AD, just some mentions here and there. I would assume they sound more similar than not, being that the apparent goal for both headphones was a neutral sound signature, and using the same driver......