I love the noise cancelling and more importantly for me - the microphones. These are the ONLY headphones that can isolate background noise properly when on a call. I can sit in a room with the misses both on a call and she can't hear me, I can't hear her, and our call participants can't hear the other one!
In relation to sound quality. These are again top notch! Better than the QC35ii I also regularly use. Overall these are the best wireless headphones I've ever owned.... HOWEVER there is one major issue - the SOFTWARE.
The Software is horrible! It doesn't consistently connect to the headphones and is required for swapping sources. It's also riddled with bugs - the latest firmware has introduced stuttering with multiple devices connected, poor battery life (think 14 hours not 20), and a large number of complete bricking cases. Bose has left this firmware in the wild for 5 weeks now without an update or rollback.
They seriously need to up their game here. These are seriously expensive headphones and the experience shouldn't be this way.