I agree it does offer something different. I enjoy it's unique presentation but when people say it's natural I can't take that seriously I'm sorry. There's a difference between showing bass levels and a realistic presentation. The Nighthawk still has a boost in the mid bass and this is back up by all graphs and also reviewers like Tyll, Marv also noted the mid bass hump. I do see that it will play heavy bass in the recording but the mid bass doesn't just make things sound bassy, it also influences the tone and gives them that warm tone that they have. It sounds sultry because of it.
What makes the Nighthawk unique is it is a U shaped headphone but it's warm, not aggressive with stock pads. Most U shaped headphones are on the bright side but the treble isn't boosted too much. There are treble peaks but it's hard to find with the stock pads and it will depend on how good your ears are. The Signature of the Nighthawk is hard to escape as it has that reverb and warmness that follow you so it's always obvious you are listening to a headphone, the newest LCD-2 and HD650(On a good set up) Sounds like real life, there's differences and it's not always obvious I'm listening to headphones.
I honestly feel people want to love this headphone because it looks nice, has good innovation and an interesting sound but most just can't get past the colouration while many, have been unsure but are also influenced by others praise and Audioquest information page that they eat it up and believe this is really what music sounds like..I'm sorry I don't mean this to offend anyone but I'm just calling it like I see it.
I personally fit in the category where I appreciate what it brings and use it as a second headphone. When you've heard the best headphones in the world you tend to see faults easier. Some headphones are boosted like the Beyers, HD800 but they are poor comparisons because they are boosted to extract detail. I think the Nighthawk is just a different flavour that hasn't quite found a place in the headphone world yet as it doesn't really sound natural, it's warm, bassy but also has decent plankton extracting capabilities. It's a difficult one to fit into a collection.
Also when people criticize the Nighthawk the couple of replies seem ot be, "You don't like accurate you want boosted highs and mids) Erm no! I want a headphone that doesn't sound congested, sucked out in the upper mids and natural in the voices! Still, I like the Hawks because it offers that "different" we all seek but don't always have to courage to seek.