The QC35 series 1 that Bose offered as a replacement for my dead and out of warranty QC25 arrived today, and I'm surprised by some of the differences.
Build quality actually feels noticeably more solid than the QC35-II, with things like the headband adjustments being stiff and rigidly holding their position rather than loose, and the buttons having a clicky tactile feel rather than being mushy.
Unfortunately I don't have the two to compare side-by-side, but comfort also seems to be better with the series 1 QC35.
As far as I can tell they look the same, though it's possible that the headband is a slightly different shape (more like the QC25). The main difference seems to be that the ear pads are much softer.
I don't know if these differences I have noticed are just quality control things, or slight changes they made for the sake of durability or cost, but it was unexpected.
The carrying case is a somewhat uglier design with a "badge" for the Bose logo rather than being printed on, but on the plus side, it comes with an airline adapter which was removed from the QC35-II. The 2.5mm to 3.5mm adapter still lacks an in-line remote/microphone though.
The voice prompts are softer (rather than 'shouting') but also spoken at a slower pace.
Related to the voice prompts, I think I forgot to mention before that you can also quickly change paired devices by hitting the Bluetooth switch without needing the app. The first time you press it, it tells you the devices it is currently connected to, then each time you press it, it will read out the name of previously connected devices, and connect to whatever one you stop on. So its connection management is even better than I initially thought.
I don't miss the Google Assistant/Alexa/ANC strength button on the left side, though I might if I used those services.
And it's a minor thing, but there's a slight pop when playback stops and the headphones switch to idle, which was not present with the QC35-II (or Sony WH-1000XM3).
Despite the softer ear pads, the noise cancelling is still noticeably improved if I press the earcups against my head, and the noise cancelling is still affected by whether I am wearing glasses or not - though it's not quite as bad as the QC35-II with the firmer padding.
This was not the case with the Sony WH-1000XM3 (a good thing) though after using both headphones for a while, I noticed that Sony's ANC was affected significantly by movement of the headphones when walking or running, while Bose's noise cancelling was barely affected at all.
I also noticed that sometimes Sony's ANC would suffer from resonance which was mild, but unpleasant. I've never had that happen with Bose's ANC.
One last thing that I noticed after using them for a while, and with multiple devices, is that practically nothing other than Apple devices seems to support AAC.
I was hoping to add a longer range Bluetooth adapter to my PC, but I cannot find an AAC-capable Bluetooth adapter for my PC at all - whether it's the standard 10m or a longer range one. aptX adapters are rare, but do exist.
So that is one downside to Bose only supporting SBC and AAC, while Sony supports SBC, AAC, aptX, and LDAC - though no aptX Low Latency for gaming.
I think that none of these wireless/ANC headphones is ideal yet, and picking one is selecing which trade-offs you are happy with.
For me, the convenience and superior connectivity makes Bose a clear winner, but if you only need to pair to a single device, or use Android devices and are concerned about audio quality, the superior codec support of Sony's headphones may be the better choice for you. I really don't like how they handle connectivity, the slow controls/interface, or just how much larger they are though.