I got a D7100 set a few weeks ago, I'll have to say I'm not impressed and will probably end up ebaying them.
The circumstances are, I had some AH-A100 which I loved, they were as damn near to perfect as you can get in my humble opinion. Then a few months ago I noticed they'd cracked on both sides where the cup holding arms formed a Y shape. Since they had a very long warranty, I sent them back to the dealer who returned them to Denon. After a month of waiting, I found that Denon were unable to repair them (not surprising, every model with that cup holder design has a rash of similar complaints on Amazon). They offered me a credit note to cover the original £500 asking price, but the dealer didn't have anything I liked the look of in that price range, given that I like wooden cups and needed something which was totally closed as I mostly use them in an office. They did have D7100s marked at the full and terrifying RRP though, and the dealer just sent me a pair as a replacement. Top marks for customer service there, looking at the currrent actual street price, I didn't really lose out in that respect.
I've let them burn in and used them for about 30 hours now, the sound is just a mess compared to the AH-A100. Unfortunately I lack the knowledge to properly describe what it is that I don't like, and while the initially over-trebled sound definitely changed from hour 1 to hour 30, the sound is just .. rough and lifeless in some way. Additionally I'm having to jack the player (an iAudio X7) up to 25 or so instead of the 10-13 I ran it at before, which is slaughtering the previously amazing battery life. Bizarrely, my Motorola phone which didn't play well with the AH-A100 and always sounded rubbish before, seems to drive these just fine - going as far as to sound passable. I thought higher impedence headphones were supposed to be harder to drive so I don't understand why the D7100 at 25 ohms seems to be more of a problem than the AH-A100 at 32 ohms.
The other problem is they're very heavy, very large, and you have to essentially wear them slightly tilted forward to avoid them slowly slipping backwards due to the off-centre design, far less comfortable than the old ones although the ear padding material is high quality and isolation is excellent. I don't know who thought the off centre design was a good idea, it's not. It looks bad and fits poorly.