As a few others have said, IMO there's no perfect single pair of headphones. I've now owned or own... AirPods, PowerBeats3 and BeatsX. Each one of them is different and they all have their pros and cons. All of this is just my opinion and as with lots of things, very subjective, but might prove helpful for anyone considering a new set of headphones.
In-Ear Fit - AirPods are the worst for me (probably my ear shape) but improved a lot with those silicon skins. PB3 are ok for me, but as I used them mainly for running, I usually had a hat of some sort on and that helped with fit. BeatsX get a good fit even without using the added wingtips.
Seal & Sound Isolation - Airpods are really poor, even with the added skins which actually give a good seal and improve the fit, only to let-in a lot of background noise and if I'm outdoors in a city, passing traffic means I have to turn them up really loud. At home, office or outside with little traffic, they're actually good. PB3 are next up - they give a slightly better fit and seal, but still let in some background noise. BeatsX give a really good seal, to the point where it can be a strange sensation - maybe its just me, but the combination of in-ear headphones which block nearly everything out is a weird one, especially when running.
Audio Quality - I don't think there's much between any of them in terms of actual quality, but they all take a slightly different approach and are affected by their respective fits. I really like the sound quality of the Airpods in a quiet setting - music is crisp and the different sounds are distinct. The two Beats ones take the approach of turning things up to 11 with mixed results. Outside running, I preferred the sound of the PB3, they seem to be a bit more bassy which helps when out and about. Sitting at my desk, the BeatsX sound better, less bassy and loud, but I still prefer the Airpods.
I use the Airpods all the time for voice calls and having asked people, they are surprised to hear I'm on a handsfree set. Both Beats seem to use the same remote mic and audio quality is ok, but apparently its easy to tell i'm on a set of headphones due to the extra background noise they seem to let in.
Design - PB3 is a well established design, but that cord with remote can get a bit flappy and can pull the headphones out of your ears a wee bit depending on what you're doing and how you're wearing them. For faster road running I found having the cord at the front was best, but for offroad hilly stuff, round the bac was better. BeatsX design works surprisingly well. I really didn't notice the two rectangular bits - they sit quite comfortably on your neck, the magnetic earbuds work well, but I did get a bit of cable noise when using them in the office with the cords rubbing against clothing. They're nowhere near as heavy (relative term) as those other bluetooth ones with the plastic band which goes round the back of the head.
Airpods are still way ahead for me and the most "Apple" product they've made in years. Until you've used them and got used to them, its hard to describe just how quickly you forget you're even wearing them - they're so light and no cable at all is a big deal.
Usability - The Airpods are simply amazing... although Siri still sucks. Adjusting volume and skipping forward using watch or phone works well, but when you jsut want to turn the volume up or skip track, having to tap, talk to Siri and then wait is a PITA. But in all other ways the Airpods are the template for all headphones. Once again, until you've owned a pair, its hard to get across just how revolutionary they are and how quickly you get used to the little features like audio stopping when you take one out to speak to someone. The battery life is amazing with the tiny case - I just charge it occasionally and they just keep running and running.
Both Beats products use the same simple remote which is very effective to use on the go although the selector button in the middle can be a bit fiddly when running. You get 12 hours of battery life with the PB3 and 8 hours with the BeatsX, both support fast charge and I've easily had the claimed battery life on both sets.
The W1 chip with instant, hassle-free pairing doesn't seem as reliable as I'd hoped, especially when it comes to switching between devices seamlessly, especially if one of those devices is a MacOS based one. Seems to be a common problem though and one which will hopefully be resolved through firmware updates.
Summary - I really want to like the Powerbeats 3, but the truth is, I've had two pairs fail on me this year. It appears the remote unit just isn't waterproof/resistant enough and seems to be a common fault. Which is a real surprise given the work Apple are doing in improving water resistance on their phones and the fact the PB3 are marketed as being designed for workouts. BeatsX uses the same unit so I don't have any confidence it won't go the same way. The design in the BeatsX isn't for me either - its more bulky than the PB3 so why would I use them for running? They lack functionality of the Airpods, so why would I have these and the Airpods.
I do a lot of running and keep going back to my pair of Soundpeats Q9A headphones which are lightweight, seem much more water/sweatproof and are about £30 on Amazon. Their sound quality is as good as either of the Beats sets when outside.
If Apple made a version of the Airpods which was properly in-ear with rubber buds to give a better fit, I'd happily pay twice the price. Make that three times the price if they sort Siri out - even if there was a set of common Siri commands cached on the Airpods, that would be a big bonus. Obviously you can programme the tap gesture to be different on each one with ios11 which will help things.
I can see me ending up with three sets..... The Airpods for the majority of the time; SoundPeats for running and a large set of traditional headphones for listening to vinyl and music from a home stereo.
