Everything is in the title: build quality, sound quality, ergonomics, usability, there is not much to complain about. If I had to quibble I would say that the keys "Next Track" and "Previous Track" are not obvious to click blindly, during training, for example. And unlike others I liked the shorter cable is a bit as I grip the neck of my shirt for the sport. The supplied headphones are very good for use phone / music mobility (level headphones we buy ... but only 20). The USB Charging Cable is quality and Sony provides three sizes of earbuds. The NFC pairing is childish and very easy classic mode too (I also use it with a Bluetooth transmitter Aukey). In the end I am very satisfied with my purchase.