Since how this compares against the Bose QC 35 is what many want to know, here are my thoughts having used both.

Music Audio quality- The Sony MDR-1000x is better than the Bose 35 hands down. Don't want to use all the technical terms about ranges and what not, but for what it's worth, if you want a great music listening experience, these are the headphones for you.

Noise Cancelling- I wore the Bose QC 35 while playing music on the streets of Manhattan and to all intents and purposes I was in a sound cocoon, this is without fidling with the (non existent) controls . I did same with the MDR-1000xs on the streets of LA, it took me probably an hour and a half of tweaking the settings to get the same level of noise isolation, and I still don't think I've figured it all out. If you want a straight out of the box solution, go with the Bose, if you want to be able to tweak what you hear and how you hear it, and have the patience to experiment, go with Sony. Noise reduction in the real world seemed to be on par.

Bells and Whistles- See above. The Bose is a plug and play device that's a one size fits all, the Sony is one which requires you to fine tune it. Having said that, I think the controls on the Sony are much better than those of the Bose.

Bluetooth- Pairing the Bose is a snap, knowing what they are paired to is also as easy as pie. The Sony on the other hand require some work, however, if one has an NFC enabled device, then some of that work is eliminated. Having said that, for ease of pairing (and switching), Bose is the winner.

Price- Sony comes in at $50 higher. If you want more control of how you use your headphones, the premium is worth paying. If you want the path of least resistance, it isn't.

Look and feel- The Bose feels lighter and is more comfortable based on the number of times I had to adjust each pair of headphones for comfort. When it comes to the 'coolness' factor, I think both are neck and neck, though I felt cooler with the Bose QC 35.

Overall- Since this is ultimately a device with which to listen to music, the Sony is a better choice seeing as the Noise Cancellation is on par with the Bose but the 'sound' of music is significantly much better.

Update 1: Used this headset for a 2 hour check-in and pre boarding wait and a 16 hour flight from the West Coast to the Middle East, 2 major observations:

a) Headphones worked in Bluetooth NC mode for the entire 18 hours. Had a full charge when I got to LAX, battery was on low when I got to Qatar. Sound quality did not get degraded at all.

b) I had a woman and her toddler next to me for the entire flight, though he was adorable, he wailed on and off for the vast majority of the flight. Except for when I chose to look at him, I won't even have known he was crying. When I removed headphones to see if he was very loud or NC was just that effective, it turned out it was the latter. Attached pic is of him after he refused the cot and literally fell asleep with his head by my feet.

d) Proper programming sequence to get best quality sound and NC is :

i) NC - > Noise Cancelling on
ii) Ambient Sound need not be pressed except you want to hear ambient sound, then choose normal to hear everything around you or voice to hear just voices.
iii) If you really want to go the extra mile, press and hold NC for 2-3 seconds to start the optimizer, it will do as promised.

BTW Gentleman who said he heard a hissing noise on his 15 hour flight, I tried to replicate that, it happens if NC isn't on, just Ambient Sound.

These are my favorite noise cancelling headphones on the market as of November 2, 2016 BY FAR! I have purchased and then returned all of the current competitors over the past two months (Bose QC35, Sennheiser Momentum 2.0 Wireless, Parrot Zik 3.0 and Sennheiser PXC 550).

The Bose QC35 have amazing noise cancelling abilities and are comfortable, but I just couldn't stand the sound quality as I'm used to headphones with a flat response. The Sennheiser Momentum 2.0 Wireless headphones sounded phenomenal, but the noise canceling was barely noticable and they were so uncomfortable to wear. Sennheiser's second attempt at noise cancelling headphones, the PXC 550's were better at noise cancelling, but still uncomfortable. The Parrot 3.0's were the best of the batch, but they are too small for my ears and the battery life was a deal-breaker. I honestly thought I would never find a pair of noise cancelling headphones that would be good enough across the board for me to want to keep.

Thank god for these new Sony's! The Sony MDX1000 takes the sound quality of the Sennheiser 2.0's, the noise canceling and comfort of the QC35's, the good looks and highly functional controls of the Parrot 3.0, and thankfully nothing from the PXC550's. The MDX1000's even add some really cool new features that none of the others have, like the ambient noise pass through while in listening mode.

Update (3 weeks after purchase): I still love the headphones, but there are a couple things they lack. 1) There is no easy way to switch between more than one bluetooth source. All of the other headphones had a bluetooth toggle. 2) There is no way to charge them while they are powered on. Again, this is something that every other headphone I tried was able to do.

Wow! These Sony MDR-1000x headphones sound fantastic. I was debating to myself on pre-ordering these headphones because I already own a pair of Sennheiser Momentum Wireless, though I knew they would be out of stock fairly quickly. I decided to bite and here they arrived the day they released. I will be making a comparison of these headphones within this review, as these two models are the ones I have on hand and are the ones that many people are debating between purchasing, while also borrowing my friend's Bose QC35 for comparison.

Packaging:
First things first, the packaging of the Sony MDR-1000x is excellent, the outside is shrink-wrapped with a inner black box, similar to Bose's QC35 packaging. Upon removal of the inner box, the cover opens from right to left, similar to the book. The whole inner box is decorated with black felt material. Inside on the left of the box is the quick-start manuals and warranty paperwork, micro-usb charging cable, auxiliary cable, and airline adapter which are revealed by flipping the inner cover out. On the right side of the box is the headphone case itself and inside is the headphones. The inner case has a slot for the airline adapter with a diagram detailing the touch controls of the headphones and how to place them back into the case when you are finished listening to them.

Headphone Build Quality Comparison:
The Sony MDR-1000x headphones looked more business like and more subtle than my Sennheiser Momentum 2.0 Wireless headphones. The black coloring accents and the black leather on both earcups with the metal headband decorate this headphone without being overly noticeable. The only logos on the headphones themselves are the Sony logo on the sides. The Sennheiser headphones on the other have had a more retro style to them with more noticeable metal parts and leather accents to decorate them than the Sony's primarily plastic build. Oddly enough, though the Sennheisers had more metal parts, the Sony's weighed more at 9.7 ounces compared to the Sennheiser's 9.1 ounces. Both headphones have just the right amount of padding on the headband to make them comfortable, though the Sony headphones had more of it on the top. The earcups of both headphones are large enough for a variety of ear sizes, with the Sennheisers featuring plush leather earpads while the Sony's had firmer earpads similar to the Bose QC35's padding. Wearing the Sony's for a few hours proved no problem for me, something my Sennheiser's would have struggled with after the first hour in which it would cause pain to my outer ear because of the speaker being pushed into my outer ear because of the plush nature of the earpads. Not much heat built up within the Sony's within the first hour while walking in public and taking them, but my Sennehiser's had much more heat and after taking them off, my ears had a lot of sweat.

Headphone Feature Comparison:
Both headphones feature NFC communication for easy pairing with phones. In addition, they both feature bluetooth connectivity, though the Sony's are on v4.1 while the Senneheisers are on v4.0. Both headphones feature the APT-X codec and AAC codec, while the Sony's have the added bonus with their LDAC if you own a compatible device. Moreover, both headphones have noise cancellation, though I would argue the Sony's mute much more noise than the Sennheisers and the Bose QC35 surprisingly. Normally when I would think of a headphone with the best noise cancellation, I would go to Bose, but the Sony's surprisingly surpassed Bose in that category with these headphones, something I did not expect. Both headphones also feature auxiliary connection when the battery is drained, though the sound quality is greatly diminished compared to being charged, but I would argue the Sony's retain their sound signature much better than the Sennheiser Momentum 2.0 Wireless headphones.

Touch-Controls and Noise Cancellation:
The Sony's feature touch controls on the left side which work perfectly. 2 taps for play/pause, swipe right and left to go to another track and swipe up and down to increase/decrease volume. On the Sennheiser Momentum 2.0 Wireless headphones, these tasks are done via physical buttons located on the right side of the earcups. Cupping the earcup temporarily lowered the noise cancellation and volume of the music to allow voices to be heard, though voices would sound hollow, but can be heard clearly. Holding down the noise cancellation button enables the optimizer which plays a series of tones to calibrate the headphones to the user's head. I noticed a difference in the sound and amount of noise cancelled when I first utilized this feature. Especially when wearing glasses, the difference was clear, more noise was cancelled out and the sound was more refined. Locating this button while wearing the headphones was easy as Sony added a slight bump to the button so it can be felt. The ambient sound button was also a welcomed feature which is not hard to locate as Sony added a smaller bump to it than the noise cancellation button, it worked as intended muting various sound elements while enhancing others for the scenario needed. Walking down the sidewalks on the busy streets, I utilized this feature to hear the cars while crossing the roads and it worked perfectly. There are only 2 modes for this button, one which allows all sound to be heard by disabling the noise cancellation, and one which allows only voices while keeping noise cancellation somewhat enabled, though limited. To turn off these features, it is done by pressing the noise cancellation button.

Sound Quality:
Here is the real meat everyone wants to hear about. Compared to the Momentum's which I have been using for quite awhile, the Sony's sounded more "fuller". Drums had oddly satisfying bang to them, much as if you were at a concert. The Senneheisers had a more tighter, and cleaner bass. I would compare the feeling to hitting a drum which had more tension. The midrange, vocals on the Sony's were less refined compared to my Sennheisers. The vocals had a more brighter hollowness to them which is perfect for categories of music such as rock, edm, and such. The Sennheiser's presented more chesty vocals. Breaths of the singers can be heard easily and vocals sounded more in-person as if you were in the same room as the singers in a smaller room, perfect for categories such as jazz and soul. The highs on the Sony's are much more colored, a snare drum's sound hits more with a oomph. The Sennheiser's present the high's with just the right amount of punch without ruining the other frequencies. That does not mean the Sony's do not, just that the Sony's sound much more "fun" in their sound than the Sennheiser's which focus more on the vocals, something Sennheiser has been doing an excellent job with over the years. Depending on your music tastes, the Sennheiser's excel with more vocal focused tracks while the Sony's excel at presenting the instruments in a colored manner.

Conclusion:
Both headphones are excellent in their own respect. The Sony's will cater more to the on the go, business folks with their appearance compared to the Sennheiser's which have more of a retro look. Noise cancellation is better on the Sony's compared to both the Bose QC35 and the Sennheisers. The sound is much more "fun" and more focused on the highs and lows, much like a v-shaped sound signature on the Sony's than the Sennheiser's. The Sennheiser's have much more fuller vocal's than the Sony headphones with tighter and cleaner bass. Build quality is excellent on both of them, with the Sony MDR-1000x having a primarily plastic construction while the Sennheisers feature primarily metal, though the Sony's weigh more. Though overall, the best way to see what headphone is right for you is to try them out in person, but for now it looks like I'll be keeping these!