Sony WH-1000XM3 is the best at noise cancelling. Better than Bose now. Sound is also better than Bose. I wouldn't say the Sony is the best headphone I've heard, but its pretty good. And there is not a large improvement in sound when noise cancelling is off either, it's just a bit better at the highs and a bit more transparent. But if you are in a moderately noisy environment, the Sony's will beat just about ANY headphone because of the excellent noise cancelling.
I was at my gym next to a group of about 20 active cardio machines. The difference with the headphones on and off my head was dramatic. It sounded like an 80% reduction in noise!
Also if you can listen to them with AptX HD or even better LDAC Bluetooth connection, they are significantly more transparent, detailed with tighter stronger bass.