While this website is not about reviews, I try to command it in the same spirit I used to navigate Usenet, if it may be useful, it should be shared.
I've been lucky enough to be gifted both these earphones, as disappointed previous owners, disposed them my way.
The AirPods belonged to my wife that unfortunately can't fit them. The WF-1000XM4 were offered by a brother that's an audiophile and got himself some very expensive, custom-tip made, ones.
After one month of commutes, extensive hours in the tube, 8 aeroplane rides, multiple jogs, 6 hours Zwifting and many more typing away, I have a pretty solid opinion on what works. For concrete details on fidelity and ample scrutiny, you should read what the soundguys wrote, the critic below is just my biased analysis of having using them both for a considerable amount of time.
|weight (each bud)||5.4 g||7.3 g|
|driver||11 mm||6 mm|
|tips made of||silicon||memory foam|
Just by looking at the specs, given the difference in driver's size, I'd thought Apple would have the upper hand. The SoundGuys also prove that, objectively, the AirPods are more accurate. My experience though is mixed. I found the WF-1000XM4 extremely pleasant to listen to music. Bass had punch and trebles were detailed. Personally, I'd say it's a close match. Perhaps leaning towards Sony.
Sony is king in aeroplanes. Noise-cancelling is just on another level. With a closed back and memory foam tips, you get incredible passive noise-cancelling. When you add active suppression to that, it just blows the AirPods away.
The 35% increase in weight is not noticeable, but I can't have any of them on for more than a couple of hours straight as I get tired. Nothing beats over the ear headphones for long hours.
What I did notice was that the Sony ones, due to the memory-foam, took longer to fit. When I had to choose one in a rush to take a phone call, I'd constantly go for the AirPods as that was a couple of seconds faster.
None of these is an actual sports earphone. I'm a fan of Bose's SoundSport which has a cable around the neck and large controls you can easily manage while running. Unfortunately, most brands discontinued cable earphones, I'm yet to try the new Bose Sport Earbuds so I can't comment on those, but one thing's for sure, the AirPods Pro and the WF-1000XM4 fall short of proper sport headphones.
There's a major difference though, while I could (and did!) take the AirPods for a jog, I could not even pretend to try and run with the WF-1000XM4. Having both a closed back and memory foam, Sony's earbuds create an airtight compartment in your ear canal. That seal, the reason why they are fantastic at noise-cancelling, is also their undoing for sports.
When you run (at least when I run), there is a slight movement in your ears as you hit the asphalt. That motion also wiggles the earphones. Regrettably, as the WF-1000XM4 are airtight, that shift creates a difference in pressure that directly hits your tympanums. Painful.
After one month, I found myself leaving home exclusively with the AirPods Pro. They're more versatile, faster to engage and, letting some outside noise in, makes them safer on the streets.
I'd say Sony designed the WF-1000XM4 with a specific purpose, whereas Apple made an all-round product.
Hope this helps steer your choice.