So I'm looking for a portable headphone that is full size, because I only roll full sized. Basically, I'm looking for a closed headphone that has the sound stage of something like the HFI 580 (or any Ultrasone with S-Logic/Plus), but has the 180 degree swivel of the AudioTechnica M50 cups. The M50 is a great little headphone, but it's sound stage is cramped and basically not there. Mean while, the HFI 580 and DJ1 are excellent and have good sound stages for closed phones, but only swivel 90 degrees. I want to find some that have these qualities. Neutral sound signature is fine. Bass colored is also ok, so long as mids are not recessed.
Keep in mind that when getting the HDJ-2000, you're also paying for the materials and build quality, which makes for quite a bit of its price.
They do swivel 180degrees and have a mono switch, which is handy for DJ usage. About the sound, it's an improvement over the M50, specifically on soundstage, which is one of your concerns, specially since you are one of the people who handles S-Logic nicely.
What steers me away from them is the fact that while they are indeed an upgrade over M50, they're not as much of a night and day difference, while the price difference is far more noticeable, but going from a M50, you wouldn't be poorly served at all, along with the fact that they're oddly durable