My review of the Denon A-HD5000 headphones has just been published and you can read it here. These headphones are similar to Denon's A-HD7000s in design, though I haven't heard the 7000s so I can't say whether they are a step forward, backwards or sideways.
Here is a summary section from my 5000 review:
"So, the 5000s are special because they have intelligently and musically tuned bass. But that wouldn’t be nearly enough, if the midrange weren’t equally good. But it is. The midrange on the Denons is relaxed, clear and well-balanced. In particular, Denon doesn’t roll off the upper mid-range as some other models in this class do. The result is that the 5000s sound more open and life-like than competing headphones such as the Sennheiser HD-650s.
"Overall, the treble is well-balanced with the mid-range and bass. There is, however, a mid-treble edge that occasionally grates, though only slightly. It shows up less as a shift in overall tonal balance, but rather as a tendency to make sibilants and high frequency transients a little "sharp" sounding."
Almost any review skips some items or fails to answer some specific questions. If you have additional questions about the Denon A-HD5000, I'll d my best to answer.