I had both MDR-1000x and QC35 for a week and here is what I think:
- Sony has better midrange and sounds cleaner overall but there are two drawbacks: 1. the bass is well controlled but there is just too little of it; I am not a basshead but bass is just too anaemic on Sony, 2. the soundstage is much narrower. The drawback for Bose is that voices are less clear and sound somewhat distant, but soundstage is much better. I also have B&W P7 wireless and neither of the ANC headphones compares to B&W sound-wise, unfortunately
- Bose is much more comfortable to wear; Sony is not bad at all, just worse in comparison
- hissing sound with ANC is more pronounced on Sony, even after running the optimiser you can clearly hear white noise when not playing music, on Bose it is almost inaudible
- ANC pressure effect is slightly more pronounced on Bose
- ANC is equally effective, perhaps with a slight edge to Sony
- switching between multiple devices is a major negative with Sony, you just cannot do it. You need to either turn Bluetooth off on one of the devices, or put the headphones in pairing mode (by turning off and then off holding the button) and then reconnect (you do not need to delete pairing from your device though).
- it needs to be mentioned that while ANC can be turned off for Sony, in my perception there was worsening in sound quality with even less bass and narrower soundstage
- the quick attention mode is potentially useful but I still prefer to take the headphones off when talking to someone as people do not realise you can hear them with headphones on! I saw little point in ambient sound modes
- Sony manual states that for charging you need to connect to a computer; I was able to charge using a regular iPad charger with no problem, though
Overall I ended up selling Sony due to the narrow soundstage and anaemic bass, poor Bluetooth implementation with inability to pair to multiple devices, and less comfort than Bose.
Still thinking if expense of keeping Bose for travelling in addition to P7 is justified; I think I will keep them as once you try noise cancelling on the plane there is no going back, but if you do not absolutely need ANC there are much better options than either Sony or Bose, P7 being one of them (as someone else suggested on this or QC35 thread). I wish B&W came up with ANC version !
Good luck with your decision !