Well, I got my HE-400's. It's bittersweet. For the positive, they are far and away the best sounding anything I've ever heard. Definitely had that "wow" moment and heard tons of stuff in songs I didn't know existed. Prior headphones include Alessandro MS-1, Sennheiser HD 555 modded, and AT ATH-A900x. For the negative, I'm coming from closed headphones and after plugging them their openness disturbs my family in their home office. So one hour on them and I may have to sell or switch them out for a closed set. Wish I could just put a big glass bowl on my head and keep them. How do the Mad Dogs stack up to the HE-400 in terms of sound character and sound leakage?
Mad Dogs hardly leak at all, if any. When I had mine, I could listen next to someone trying to sleep and not affect them at all. They are super comfortable.
As far as sound goes I made a post a while back to detail my thoughts at the time.