AirPods are now available

If they add positioning, this product becomes Magic Leap without the visuals. I don't think they see this as a music device, they see it as a new platform for audio. Interesting things start happening when people start leaving one or both in their ears all day. Arrival times in your ear at the bus stop. Ask Siri for a price check while at the store, etc.

A cable to your phone makes the earbuds hard to forget. This makes it easy, but the design details have to be right for you to truly forget they are in.

I know "forget they're in" doesn't sound like a groundbreaking feature, because it's not connected to any obvious technical challenge, but I think if they succeed at that it would in fact put these in a new category.

Positional audio would seal the deal. You can walk around your kitchen and it would feel like your invisible conversation partner was in the room with you.

This Plantronics case isn't that great. You have to open it with two hands in front of you, and carefully place the awkwardly shaped headset in. You probably have to look at it while doing so. It's rather large, and the clear plastic cover looks like it can break pretty easily. It's also only one ear, and it's a $30 accessory.

The AirPods can be opened one-handed while in your pocket, and you can place them in without looking. They're also smaller, the case looks quite a bit more durable, and they work with the charger you already have as an iPhone user (lightning). The AirPods and case were designed with a broader UX scope - the entire user experience, from opening to listening to putting away - as one unified product.

The process that most hardware teams typically take is more narrowly focused on the core product hardware, rather than the entire scope of its use. If Plantronics had designed their headset with a broader UX scope in mind, they probably would have designed the headset itself differently, because its awkwardly shaped and hard to store. Instead I imagine they optimized the headset design for solely when its on-ear, and then asked how they could make a case for that shape. Such are the little differences that distinguish between regular products and category-defining ones (see also: iPod with iTunes).

All of Apple's "accessories" (things that will request charge from a host over their cable: phones, tablets, keyboards and touchpads, and now headphones) have a Lightning port.

All of Apple's "computers" (things that won't: computers that are wired for power, and devices that are wired for power like the Apple TV) have, or will have, USB-C ports.

The vague middle case is laptops, like the new MBP: they do charge over their USB-C cables. But they'll only do this from a wall-socket power adapter; they won't attempt to drain the battery of a peer device they're connected to.

Besides that HCI hint of charging semantics, though, Lightning is just physically different in a few important ways that Apple relies on: for one, the connectors are solid metal, so an upward-pointed male connector can be used as a freestanding dock. That's not true of USB-C. Apple isn't going to converge them.

I believe modern Bluetooth headphones are indistinguishable from equivalent non-Bluetooth headphones. If you can tell whether headphones are Bluetooth or not—the other components being equal—then you have particularly acute hearing. And if that's you, then you are probably a FLAC aficionado.

For what it's worth, I listen to MP3s on Bluetooth headphones and they sound great.

(Though to be clear, I've not actually researched the bit rate of Bluetooth, though I suspect it's high enough for 44 KHz stereo. To my ears, Bluetooth is indistinguishable from an analog 3.5mm connection.)