For the last 3 or so years I've been using a pair of Bose QC35's as my daily driver headphones. Competition has heated up, and the place for the top noise cancelling headphones seems to be forever changing depending on who you talk to. We already know the specifics of the Sony WH-1000XM3 headphones - but, there are some excellent features on these that make it incredibly hard to go back to my beloved Bose QC's.
For starters, audio quality is great (and I mean great). Now, I am not an audiophile by any means. The music I listen to is all over the place depending on my mood (See my last.fm here) however I do listen to some rather bass heavy music especially at the Gym so a pair of headphones that can replicate the deep end of the spectrum are a must for me. I've found these headphones to be very good at replicating the low's better than the Bose (and if you've ever tried the Bose you know these are no slouch) while still maintaining the clarity of the mid's and high's. I have these paired mostly to my iPhone XS Max which doesn't support APT-X but still, I honestly can't tell the difference in audio quality between this, and with a phone with APT-X support (like the OnePlus 6T).
Now, this is where things are awesome - and that is with the noise cancelling. These headphones are on-par with the Bose (in the sense I can't tell the difference between them) - Train and Plane noise is essentially fully blocked out and so is that screaming child or noisy kids sitting a few seats away. This is a good thing as the Bose are regarded as the best headphones in term of noice cancelling by many. There is also a feature on the Sony's that allow for you to passthrough audio around you by placing your hand on the right ear cup which is handy if you ever want to listen in to people around you however I've found that people outside of your "bubble" don't quite understand this - I still find myself taking off the headphones when somebody is talking to me because lets face it, it is courteous to.
The touch controls on the right ear cup are a frustration to deal with at times and I really wish Sony had physical buttons. I find myself often unable to pause music the first time around, changing volume is annoying at best and I find that the headphones often don't detect your gesture. I've spoken to others who bought their headphones after I got my pair and they agree with this fact. I love the simplicity of my Bose and its 3 button setup to play/pause, skip a song and change the volume. It is simple, and I don't think Sony needed to change what works here. The workaround I've found is using my Apple Watch for these functions.
Something else I really (and I mean really) miss is being able to have 2 devices paired at any given time. I've had my Bose always paired with both the laptop I am using along with my phone meaning I can fire up Spotify on my laptop and if my phone rings I can answer it with ease (which, at the same time pauses the music I had playing on my computer). This is something Bose have done really well and I'm actually yet to see any headphones do this as well.
Charging these headphones are done over USB-C and have used my MacBook charger to do this every time. Not that you need to charge them often - I find I can go a week with rather heavy use before needing to top them up. It is nice that more devices are adopting USB-C these days.
In conclusion. These headphones are excellent. I have not used my Bose headphones since getting them and noise cancellation and audio quality is truly top-notch. I've actually been recommending these headphones over the Bose to people as they're simply that good and if you've been considering them, then just do it. You won't regret them.