Okay... so I have never ready so many varying impressions/reviews on one headphone before. Especially none that I would use to describe the pair I have listened to. Could it be that there's a good deal of variation between each NightHawk or is its sound just that rig-dependent?!
Nah, I hear everything everyone is saying. It's a unique signature, and people who consider the bright, detailed headphones like the HD800 to be their ideal for clarity are not going to like the Nighthawk. It's a much smoother, more reserved headphone. It reveals detail in a different way from other cans I've used and can feel dull with some songs or genres.
I've tried them through 4 different amps and 4 different dacs, and the Nighthawks are always in the same ballpark.
What I like about them is that they cause absolutely no fatigue while still allowing you to focus on the different elements of a song if you choose to. They also provide a more enjoyable listening experience to me for certain genres (like jazz) than other headphones, while being less engaging for other genres (electronic) than some of my headphones.
People are always going to love or hate the Nighthawk, and I don't think that's a bad thing. I can't stand bright headphones because I'm treble-sensitive, nor can I listen to headphones without meaty bass. That means I loathe some flagships, but I can enjoy the Nighthawk.