Shawn has a fairly detailed comparison between the Sony XM3 and B&O H9i because in his words:
There are subtle differences between the two. But the differences are so small that no normal person should bother themselves taking the time to obsessing over the small details between these two sets of headphones.
But, let’s be honest. We’re not here because we’re normal.
No, we’re here because we’re nerds who have been known to obsess over the details that nobody else may notice.
I’m tempted by the B&O headphones but they’re more than double the price in Canada than they are in the US. That's much more than an exchange difference and at this point it’s just not worth it to me.
I’ve got the Plantronics Backbeat Pro2 noise cancelling headphones. Build quality is plastic and if you’re in an already quiet environment you’ll hear a bit of a whine in the noise cancelling. But, you’re in a quiet place so turn it off. With some background noise to kill you don’t notice the slight whine at all.
They pair with two devices and they’re auto-off feature is so reliable I don’t even think about it. It just works to pause your music when you take them off. I’ve never had a false positive.
I have more to say, but I should just do a video about them soon.