I've found the Sony XM3s to be noticably better than the Bose QC35s for noise cancelling, and the Sony's to have less of a vacuum effect at the same time. I feel that the Bose QC35s have better sound quality out of the box, but using the Sony EQ for the Sony headphones it's easy for me to get them to sound about the same as the QC35s for overall sound quality, so it's a pick 'em.
I have noticed that when you turn on many of the firmware / software features of the Sony XM3s you lose the priority on sound quality option and are limited to the priority on stable connection option. If you have third-party EQ on your device (not part of the Sony headphone firmware / software) I think you'd still have the option for the Sony emphasis on sound quality (LDAC, etc.) setting.
On the subway I find the QC35s try to suck my eardrums out whereas the Sony's are not so quick to do this and I can lessen the N/C effect on the Sony's a little (such as with the wind setting) to take the edge off of anything like that. Also, I can use the Sony's on the treadmill and not hear much of the noise from the treadmill--that's really nice.
Thanks everyone for the info on the firmware update for the Sony's. I use them with an IPad rather than an Android device--I wonder if that makes a difference.
Either way I consider both headphones to be premium products, but for me EQ'ing the out of box sound for the Sony's is pretty much a must to get them to be the equal for sound quality of the QC35s, since I have a preference for a little less bass than the Sony's have out of the box.
Hope this helps. I'm waiting for some people to quit arguing in other threads so I was browsing around.
Interesting thread and very helpful! Thanks!