I just got these today. Right off the bat, I had to switch off the horrible pads to the M50 ones. Sooo much better! MK2 owners, you MUST buy the M50 pads, they are superior in comfort by a landslide and a half! Sound wise, I actually found it didn't take away much from the sound like everyone had said. They sound pretty darn close to the stock pads, and in my opinion, better. Not to mention the comfort is just awesome now. For some reason, these are honestly one of the coolest headphones to wear on your head, because it really feels like they are hugging you. I've never had this sensation before, but I love the hugging feeling they give me. They stay put, they stay comfy, and they look great! (SRH940's are too big and goofy looking for public).
Sound wise? Well, let's just say I'm loving it so far. MK2 owners, I'd love to hear input from you weather or not these change with burn in, because if they do, they'll be even better and they are already quite good. These are officially my "party" headphone. And also the only full sized one I would take around public, outside, or just generally around places. The bass on these is just fantastic. Not quite the punch or extension of the Pro 900, but it has a lot more quantity. It's like your "swimming in the bass" rather than having the bass hit you in the form of a tidal wave. Don't get me wrong, these still have fantastic punch, but I believe the Pro 900 has a harder hit and also knows it's place more. The bass of these remind me A LOT of the XB700's bass. I actually compared the two briefly, and they are quite similar, but the MK2 is superior all around. It's like the Hi-Fi version of the XB700, without the loss of bass, yet more refined and exciting bass. It's just great, it's making me grin like mad.
As of now, I have my SRH940 and these PRO700MK2. Sitting together side by side, I look at them and think, "This is all I want. Nothing more." They compliment each other perfectly. My HE-500 is in trouble.