Build: Excellent build quality. Doesn't feel cheap like some of the budget Bluetooth earphones I've owned. The cords for the buds are flat, which means they never tangle, and the neckband is thin and flexible, but firm. It's all this soft touch matte plastic and rubber that feels really nice. I opted for the blue color and it's really nice. It's kind of a royal blue that's it crazy bright. The two little lumps on the cord where the electronics and batteries are housed look weird at first, but it's a great way to balance things out while making the whole package super slim. There's also a magnet in the bids so they sort of click together around your neck when you take them out. Keeps them out of the way. I kind of always have them on because that's so convenient. Quality, quality build. These are not the Beats of old. This feels more like an apple designed product.
Fit: They come with a few tips and a few ear hooks that go inside the ear. I found the large tips to work best (as usual), and I added the large hooks too. They go inside your ear, not over it, and they're really comfortable (same soft matte rubber). I have worn these all day with no fatigue. Almost forgot I had them in. The earbuds themselves are slightly angled in, which helps get a good seal. Because the electronics sort of test on your collarbone, the cords don't tank the buds out with their weight. Also, because there's just enough slack between the electronic lump things, they don't pull when you turn your head.
Sound: I do and have owned high quality studio cans and wired IEMs. These, of course, don't touch those in sound quality. But in terms of Bluetooth, they're great. The sound is not at all Beats-y, that is, it doesn't have booming, muddy bass. In fact, I'd go so far as to call them very balanced with a nice bass punch. The mids are clear and the highs are crisp. The low end has a punch but it's not muffled or muddy. I read some reviews that said the sound quality was poor, but I think those reviewers didn't take the ten minutes to figure out the right tip/hook combo because once they seal, they sound awesome. That's the last part of this. The seal, for passive noise isolation, is amazing. I only need the volume turned up halfway to think they sound a little too loud. And when they're at a good volume, I can't hear anything in the outside world.
Range and pairing: I know you only pair them once, but the W1 chip did, in fact, make pairing even simpler than it already is. Further, my other Bluetooth earbuds/headphones would often not connect right away or frequently lose connection. These have never, I repeat, never lost connection and have never taken more than two seconds to pair. The range is ridiculous. I've walked to the second floor of my house with my iPhone 7 in the basement and there was not degradation or skipping. At the office I get up and walk away and only after I'm really far away do I lose sound. It's the best range I've experienced.
Battery and charging: The battery goes 8 hours for me, as advertised. They take about 35-45 minutes to charge fully once empty. The best for me though, is the 25%/2hr charge in five minutes. I'll often go through my workday and drain almost all of the battery. I pop them on the charger for 5 minutes and I truly get at least two more hours out of them, enough for my train ride home. As an added bonus, they charge via lightning and come with a 6 inch black, Beats branded lightning cable. It's great to not need a micro USB charger for anything now.
Bottom line, I LOVE these headphones. They sound fantastic, have an amazing range, fit wonderfully, etc. If they go on sale again, I'd say run and buy a pair.