Using them now for a while, they are the first working wireless earphones I have used. They work seamlessly when paired with 5 devices. Even without the latest Apple OS’s you can simply activate the connection on a device, and it will switch without you having to first disconnect them somewhere else.
They are mostly reliable, only sometimes, when connected to my Mac, they have some trouble getting themselves sorted out: they can stay stuck using only one side, or a low quality codec. I wonder whether these are actually issues caused by the Mac, as I sometimes need to check Airdrop to get the Bluetooth connection to work. Also the watch intermittently has trouble connecting. It always works after turning off Bluetooth on my other devices, but this is annoying.
They fit very comfortably, and can stay in my ears for hours. My worries about them falling out are unfounded; their low weight means that even when moving the pods do not generate enough force. But be careful not to touch them accidentally: pulling a cap over your ears will surely dislodge them. As they are very easy to put in, I reach for them even when only wanting to listen for a few minutes.
Mildly annoying is only the limited integration with Siri. When you have set it up to only be accessible with an unlocked device, Siri stops working when your device locks. It would be nice if Siri would stay available until you remove the pods from your ears.
Addendum: The AirPods remain pure magic, the cord was such an annoyance. Unfortunately switching between the devices can fail. Sometimes toggling airplane mode helps, sometimes it requires a reboot. Once a fortnight it remains a minor niggle, but it really should be fixed. (May 2017)