Quick Summary: (4/5)The Sony WH-1000XM3 is a great pair of headphones that hold their own against the tenured Bose. The Sony's provide a fun and full listening experience to a wide array of music genres that will make most perfectly content with their purchase. Bose's QC headphones will provde a more refined and pleasent listening experience especially for the discerning listener and will provide a stronger noise cancelling performance in a home or office setting. The stronger sound signature of the Sony will hold out better in a lounder atmosphere such as a plane, train, or automobile with its stronger bass performance. The Sony's lack the grace and balance of the QCs, but will provide a more familiar experience to the majority of listeners and will appeal more to someone who likes the sound of Apple's Beats, but is looking for a more professional or subtle design.Full Review:For the Sony WH-1000XM3 ($350), I will primarily compare it to the Bose Quiet Comfort (QC)($350) since even though they are all in the same relative price range, they are technically closer in price and age. I will also provide a little comparison to Bose's NC700 ($400) and Sennheiser's Momentum ($400) in the summary. Also, I will primarily discuss the pair of headphones in question and how it relates feature-wise to the Bose's Quiet Comfort (not QCII) headphones while refraining from giving too many details about the others, since you can read more specifically about those pairs individually in the review posted under their respective products. The reason for that is mainly to keep the review from becoming a master's thesis in subjective preferences. :)Initial Impression:Starting with the packaging. Simple and straight forward. The outer shell has a nice texture to it, but sliding out the insert with the headphones in it reveals a very simple package structure made up of just the case holding the headphones inside a box. However, the case itself feels really nice and has a sleek color palette. Very appealing to feel and look at in my opinion. Although the case is a touch bigger than the one for Bose's QC, it does a better job of holding its headphones. The QC's case always feels uncomfortably tight when putting them away. Sony's case neatly holds everything comfortably (without having to squish them in to zip it closed). The case is stiff, but not really hard. The inside is the same as the QCs with a soft microfiber feel to it. The headphones fold up inside with three little slots to the right for (inside to outside) the airplane adapter, 3.5mm aux cord, and USB Type-C charger cable.The Headphones:When I first picked them up out of the case, they felt nice. Soft plastic with a good feel to them. The plastic has a sparkle to it with a matte finish that resists fingerprinting decently. The band of leatherette on top is soft and has good cushion. Similarly around the ear cups. Very soft and nice to the touch. Not as stiff as the QCs. The click of the band when expanding it is satisfyingly stiff. At the top of both ear cups, you can see one of the microphones in a rose gold finish. Some other smaller holes are hidden around more subtly for the NC array. I feel this is a minor plus for the Sonys. The QC's microphones are a little more prominent and pick up wind a lot more outside. The USB Type-C port is at the bottom of the right cup with an indicator light. The left cup has the power button along the bottom back with the button for toggling the noise cancelling level just above it. Inside the ear cups, there is microfiber layer covering the drivers over a layer of foam. Overall the Sony's feel a little lighter than the QC's but also feel just slightly more flimsy when handling them. But the design is also more appealing and fluid and frankly more premium.When comparing the headphones while putting them on, the QC again feel more snug and naturally isolating before turning them on. The cups feel like they form a better seal given the stiffer covers and the QC also have angled drivers that leave natural room for your ears inside the cup, making the headphones not feel like they are sitting on your ears, but rather around them. The Sony are by no means uncomfortable, but may tend to be less comfortable for longer wear times and might make your ears prone to getting hotter.Sound Quality:For starters in this section, I will compare the noise cancelling. Upon turning the Sonys on, you are greeted by a woman's voice that sounds like it is in a tin can or cave when she speaks. When the NC kicks in, it does a darn good job of removing ambient sound and muffling people talking somewhat. It feels very close to the NC of the QCs, but I would still give them a leg up because the Sonys have a much more noticeable white noise factor playing whereas the QC feel more like they just sucked the sound out of the atmosphere around you. For the traveling folk (I primarily wear them in a typical office setting which any of these work plenty well for), I would say given the more aggressive, forward, pronounced sound stage with the Sonys, you will find them blocking sound better in a car or plane without the sound (especially on the lower, bass end) being washed out. The QCs have better NC, but the sound is softer in general so the sound still gets overwhelmed in a car/plane. I am not saying the NC is not doing its job, just that what you are left with is weaker with the QCs because the sound itself is subtler and more refined so you have to turn them up louder to make up for this.Now, it is difficult to judge sound since it is so subjective, but I will try to give my own impression of what each headphone may be better for. I listen to a wide range of genres, so I can appreciate many styles of music and how they are represented by different types of headphones and speakers. First, the Sonys bring a more forward sound. The sound stage isn't as wide as the QCs. Instruments get mixed together and lost in the fray. The sound of the Sonys feels more akin to that of Beats Studio. The bass is more pronounced and punchy which may be more appealing to some. If you prefer a balanced and clean representation, the QCs will serve you better. As you turn the volume up, the Sonys also lose more of their balance and can become muddy. The QCs give more of an impression that the music is playing around you, while the Sonys just feel like they're playing music. (if you really want to feel like you are on stage with the music, Sennheiser's HD800S is king. The HD700 or HD660S do a good job too at a better price, but these are all studio headphones, so totally different use case to begin with.)Where I really felt more of the performance shining through came in the Rap, R&B, or even some EDM/House area. I can definitely appreciate Sony more for some 2pac, Destiny's Child, Infected Mushroom, or Daft Punk. They are little too aggressive for music you may want a finer touch with such as jazz or opera. When listening to some Kenny G, David Benoit, or Keiko Matsui, you get that groove, but the fine details and intricacies of the instruments are sacrificed. Also, the sharp trills of the piano keys and saxophone are a bit much at higher volumes. The visceral in-your-face nature of the sound also makes them pretty fun for bands in the vein of Disturbed, Five Finger Death Punch, Pantera, and Metallica. Going a bit further that direction, with the likes of Eluveitie and Slayer it will be more likely to give you a headache from the unsubdued highs and thrashing sounds. Taking a couple steps back and going for some more classic rock like the Eagles, Journey, Gerry Rafferty, etc., the QC will perform better, but they are fine with Sony's headphones. Finally, when listening to music with a gentler atmosphere like Norah Jones, Ray LaMontagne, Ludovico Einaudi, or Celtic Woman, I would have to give it to Bose's QCs again but the Sony did liven them up a bit in a way.Features:Both Sony and QC have three levels of NC. High, Ambient sounds, and off. The QC handle this a lot better. The mid level for the Sony feels worthless and clumsy without audio playing. It almost sounds better being turned off. On the QC, the mid level provides a good balance and allows you to wear them outside on a windy day with reduced noise from the wind in the NC microphone. However, in the case of the QC (instead of the QCII), you need the app to change the NC level.The QC claim 20 hours of battery, which I have thoroughly proven to be true in the years I have owned them. Sony's claim 30 hours, which I have also found to be true, but I haven't had them nearly as long to see how they hold up over time. Also having had the QCs for longer, I have had to replace the ear pads after about 2 years. This process was easy and made them feel and sound new again with the better seal of fresh pads. The process for both headphones appears to be the same.Call quality is great for both headphones. I also use them for Skype calls from my laptop at work where they work great. However, this is one of those places the Sony completely dropped the ball. Bose's QCs allow two devices connected at the same time, and you can switch seamlessly between them which makes them great for the office. I have them on the laptop and my phone at the same time. I can listen to music while working. When its meeting time, I just join the Skype call and it immediately picks up. If I get a call on my phone, it switches back over. When I am done, music is ready to go. I don't have to touch anything. Next time I turn them on, it picks backup to the laptop and my phone immediately.Both charge fast. Just a few minutes will give me a couple hours of use in a pinch. Both also have apps. The Bose app is laid out better and more useful, but neither are really great or even necessary except in the case of the Bose being able to sync two pairs of Bose headphones to play the same music or audio through both. This may be a good deal for a couple seeking to both watch a movie on a plane or something. I have done this a couple times and it works well once setup. It is a nice feature in favor of Bose, but I haven't really found a lot of use for it in reality.For the Sonys, you have the features with the right cup having touch controls. This is fairly slick and works better than I expected. It only took a couple attempts to get the hang of it and it is responsive. Swipe up and down for volume. Swipe left and right for skipping tracks. Double tap to play and pause. And finally, if you hold your fingers on the right ear cup, it will turn the volume down and turn on the external microphone to catch ambient sound if you need to talk to someone really quick without stopping your music. A nice feature, but I personally haven't found much use for it. Might be useful for people in a bigger city like NYC walking around with the headphones constantly and you don't want to take them off every time you need to listen for a moment.Conclusion:Sony's WH-1000XM3 are no slouch and stand up for themselves at this price range. For someone looking for a pair of headphones with solid noise cancelling, flexible and diverse performance across genres and premium features, you won't go wrong with these. I dock them to 4/5 stars simply because in my own opinion, they fall short of Bose's QC series at the same price range in the overall quality and balance of the sound, noise cancellation ability, and the ability to connect to two devices at once and seamlessly hand off between them which is extremely handy for business people in today's multi-device world. Now, for my brief mention of the slightly more expensive options in the Bose NC700 and Sennheiser Momentum. If you are willing to step just a bit further up to the $400 mark, you will get even better quality, better noise cancelation, more premium feel and just overall better devices. However, I will propose that with the Sony or Bose QCs, you would not go wrong. For the majority of people, I would not say the extra money is worth it for the marginal increase over these headphones. It will mostly come down to your preference in sound.I will try to keep these reviews updated as time goes on and if anything comes up. Feel free to ask any questions and I will give a response when I can.