Given the amount of useful impression/feedback already, I'm not sure how useful this post will be, but wanted to share my early thoughts a little. To give a little disclaimer, I'm only relatively recently venturing into the realm of headphones. Might I say, there is a staggering amount of information out there. Also, not terribly bank account friendly.
After listening to the new headphones a bit, there were a few tracks that I thought left points of interest regarding the characteristics of the headphones so wanted to talk in context of those tracks.
LTJ Bukem (the lingering bass notes that form the background pulse of your typical progression sessions track I find to give a good sustained exposure to how the bass will be portrayed - usually this is a nice way to test for bloat-y/flabby uncontrolled bass for me as well) the X2 did quite well here. Not sure exactly why I was kind of expecting it to not do quite as well, but the bass was well sustained and organic in sound while being well controlled. Almost oxymoronic to have lazy bass notes being portrayed organically yet controlled (this is clearly a good thing to me). Nicely done then, X2. So basically, I'll consider bass heavy/heavier genres fair game on these headphones (so far), and unless you're stoutly in the basshead camp I think most would also appreciate how bass is presented. The extension is nice. The bass is controlled and tight even when lazy or merely for background tone.
Bert Jansch - Angie/Anji
A song that I much enjoy. But a song that usually pulls out sharp sibilance attacks that I unfortunately have issues being able to deal with, in certain headphones. The notes were clean, even the intentional sharp loud twangs of the strings came in crystal clear, yet no pain. Huzzahs all around. No harsh shrieking raking on my eardrums. Hopefully this is the case for majority of listening I do. Fingers crossed etc.
If you want another song to see if there will be some screeching, you can always try
Ray Charles' - Hallelujah I love Her So (I've had issues with the sax and trumpets on certain headphones).
Chet Atkins playing Jerry Reed's - Baby's Coming Home
I'll start off by saying, I was surprised by how it conveyed the mood of the song so well. This is of course after considering the obvious factors like the purpose of the song, tone of play, recording factors etc. The creaminess (not a fan of this descriptor, but really it was the apt word to describe it I promise) of the guitar play, especially during the cascading harmonics, all cleanly came through. Also wanted to say the percussion was very well portrayed here. Was a nice treat for me. I'm starting to understand why the X1 was generally viewed as a good all-rounder (especially when considering price point).
As an aside, headphones are undeniably fun to me when you're doing another pass of a song to listen to a different part or instrument or aspect of the sound to make sure you're correctly conveying what you want to convey and instead just find yourself with your eyes closed, enjoying the music with a stupid smile on your face. Then having to re-listen because you forgot to write as you're listening. For the 4th time.
I honestly don't quite remember where I got that these headphones would not be good for classical, but that's what I thought going into it. But pieces like Chopin's Op. 10 No. 4 sounded quite good, as did Op. 25 No. 1. Both pieces vying for clarity in different ways from the headphones (aggressive vs. not). The recordings I listened to were performed by Murray Perahia (for those that wanted to test). Op. 25 No. 12 (also a good piece) had a few brief parts I thought sounded slightly muddy but overall good. From the little listening I've done, while classical might not be its laser focus, I think it's certainly capable of doing quite well.
Thanks to a friend all obsessed with the new Donkey Kong, I did have to share this one track:
Seashore War. What would you call that in the beginning? I'm assuming they used chimes and put a filter on it and maybe edited it a bit? But whatever it is, it's the most melodic sound of "actual" ice I've ever heard. A fun song that sounds good on the X2. Makes me want to eventually go buy a Wii U for this game.
Funny how initially, given that there seemed to be a decent amount of impressions and feedback already regarding the sound characteristics (by those with better knowledge and set ups), I really only wanted to briefly comment on the aesthetics of the headphones or more specifically the color. But that ended up with me uselessly rambling about my impressions of the sound above ha ha. Sorry
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Aesthetics (color scheme):
I'm one of those that preferred the X1's color scheme over the X2. Since in the pictures I saw, the X2 looked slightly flat, as in it lacked depth to me. Guess the initial impression was that it was a little too "stealth" with the tiniest hint of the "gamer gear" type feel with the just straight black that I thought it was (the same small concern in the back of my mind I have for the K7XX which I ended up also ordering). But in person, it is tastefully multi-tonal. The chrome accents of the grill and the headband goes well with the matte, soft grey of the cups and the black of the velour pads. But what I liked most, was the subtle (perhaps maybe because I never noticed it in the pictures) dark gunmetal-ish brown hue of the ring that holds the cups. It's very nice. Or perhaps it's just the lighting here playing tricks on me, but I did carry the headphones to different light sources and stare intently at the ring like I had potential mental issues to onlookers, just to be sure. Since in certain types of lighting the ring looks to be a dark charcoal grey. Either way, the "tanned bronze" ring brings it all together for me, and breathes life into a potentially sterile looking headphones. But it luckily isn't. I very much like the styling of it, and could easily personally consider it more on the timeless side of the spectrum versus trendy when it comes to the styling of the headphones. Which is very in tune with what I prefer. So if this was a concern for some of you, as it was for me, I'll say it definitely looks better in person.
Misc.:
I know there were some fit issues with the X1 for some, so thought I'd mention that I have a head I would say is somewhere between medium and large. And out of the box, I didn't have any clamping issues, no stretching required, it just sat comfortably on my head. What I initially wished were slightly heavier feeling headphones (due to feeling the lightness of the headphones didn't quite match the visual image I was getting from the "quality" feel department) turned out to be better that it wasn't. Since, once it's on the head, I honestly kind of forget it's there. So basically light and comfortable. I've been wearing these for about 5+ hours straight and don't have a single comfort issue. The weight is pretty well distributed on the head. Not sure how much of a role this plays, but just in case it matters these are my first velour ear pads. I will say that while I enjoy the sound and also their looks, I wish the leather that they used was a bit softer. It cheapens the feel a bit with how hard and slightly plastic-y it feels. But that's hardly a big gripe (and considering the price, really a non-issue). Merely nitpicking a bit to mentally assure myself that it's not just 100% honeymoon phase with the product doing the talking (hopefully ha ha).
While I haven't tried aggressively throwing specific songs at it to test the headphones yet (mostly been akin to just A.D.D. enjoyment of a child aimlessly running about enjoying new headphones) clearly I have a lot more listening to do (more music, try some movies out, gaming too) to better understand these headphones, but going on only a day of ownership so far, things are looking very fun. And isn't that why we're all here? Enjoying our music and sounds.
Listening was done off a laptop with an O2 amp. From my brief moments trying them, they sounded good straight out of both the Nexus 5 and the Cowon J3 as well. A nice bonus if the situation arises. Although, as expected they do leak a lot so that might negate some of the benefits of bare bones portability.
Not saying that X2 should win but just make sure You don`t "rush" giving final verdict 
They are not flagships but 2nd best of Senn and Fostex. Still expensive for most people unlike X2. I must say though, X2 is to me preferable to HD800 and TH900 as well. TH900's highs are piercing which I cannot tolerate. HD800, while technically much better, is less musical. HD800 is like a surgeon. Great at his job but not emotional. X2 is musical and technically better than HD650 with great bass, so it's perfect for me. I think it's like a better HD650 which doesn't need amping which therefore results in awesomeness. 