I kept hearing about these 'Bose killer' headphones. So I finally tried them out, and they're seriously good.

Design is up to you. The Bose QC35 II have a classic Bose design that's perhaps a little too classic these days. The Sony XM3s have a sleeker modern and minimalist look.

The Bose QC35 II are slightly more comfortable.

The QC35 II feel lighter on your head and have softer ear and headband pads than the Sonys, and they're more comfortable as a result. The Sonys are still comfortable, though.

Anyone and everyone will be happy with the sound produced by both these headphones, but the Bose sound better out of the box.

Both headphones deliver great sound that anyone would be happy with, but I personally had to make a few adjustments with the Sonys to get the sound I wanted.

Out of the box, the Bose sound a little better than the Sonys, at least in the way that I like music to sound. I like clarity and brightness, as well as ample bass, and the Bose deliver. The Sonys sound slightly more muffled out of the box, but you can thankfully change the way they sound with the Sony headphones app, and it makes a world of difference.

In Sony's app, I change the equalizer to the "Bright" setting. Indeed, a "bright" sound is exactly what I like, and the Sonys nail it.

Noise cancellation: Both are excellent, but Sony edges out a win

After testing out each pair of headphones in planes, subways, noisy New York City, and the office, I've found that both the Sonys and the Bose do a fantastic job of cancelling outside noise, but the Sonys have a slight edge.

Still, both headphones shock me as to how much sound they block out. When I take either pair off my ears in the New York City streets or the subway, both of them make me wonder how I ever managed to stay sane without them.

Other little bits and pieces.

The Sonys use USB-C for charging, whereas the Bose use the ancient micro-USB. I'm happier to see USB-C, as that's simply where tech is going. More and more of the devices that I own use USB-C, which means I'm more likely to have a USB-C cable lying around in my bag or on my desk for charging the Sonys. For the Bose, I'd have to specifically bring out a micro-USB cable, which at this stage would purely serve to charge the Bose.

Micro-USB is slowly being phased out, and it's a shame that the QC35 II headphones are yet another relatively recent accessory that will keep you with a foot in the past with micro-USB.

As for battery life, each company has its claim. Bose claims 20 hours and Sony claims 30 hours. I didn't really notice much of a difference between the two. I just charge them when I need to, and I never felt like I was constantly charging either of them.

The controls on each headphones are OK. The Bose use buttons and button combinations to control your music, while the Sonys use taps and swipes on the exterior ear cups. I find the taps and swipes slightly more intuitive to use, but it's still not ideal. Few headphone makers — if any — have properly figured out built-in music controls.

Both headphones come with voice assistants, like Google Assistant and Amazon's Alexa. But this is a non-topic, in my opinion. I've only ever used smart assistants on headphones for quick testing, and never found a good use for them. Maybe you will find a good use for them, maybe you won't. At least voice assistants don't take away from the headphones.

There's one thing the Bose can do that the Sonys don't, and it could be a deal breaker for some.

You can connect the Bose to two different devices at the same time with Bluetooth, which is great for seamlessly switching between the connection with my phone and the connection with my computer.

Shockingly, the Sonys don't let you do that. They can only be connected to one device at a time, and it's more of a hassle to switch between devices than it is with the Bose.

So which pair of headphones should you get if you're looking for great sound quality, noise cancellation, and functionality?

This is a tough one.

On one hand, the Bose sound great out of the box. On the other hand, the Sonys have slightly better noise cancellation, and you can tweak the sound to your liking either in the Sony headphones app, your audio streaming app, or your phone's sound equalizer settings.

The major thing for me is seamlessly switching between at least two different devices, and that's why the Bose stake their claim over my ears. For this one very reason, I'd recommend the Bose over the Sonys to anyone who wants to use their Bluetooth headphones with more than one device. With that said, if you're confident that you'll only use Bluetooth headphones with your smartphone or your computer, the Sonys will make you happy.