Get it few dsys ago... The good: build quality excellent, UI overall nice to use, battery life, high output power. The bad: volume slow to change up-down and expecially the sound! Here what happened, after pairing with quad BA earphones Ultimate Ears UE900S :the first music I listen is ok, very good quality and expecially in some tracks there are small details that I have never heard before, making listening more exciting, with a light emphasis on lows that I don't dislike at all. Until I listened to Jean Michel Jarre's Equinoxe (CD rip, WAV 16bit 44.1khz) Lows, mids and mid-higs are well maintened, but some high frequency synth effects are heavily distorted making listening unpleasing! I mean: SOME effects,
with particular pitch and modulation, not all, otherwise I would think of a defective unit. I read the player is based on a DSP+DAC architecture, so I think the DSP works too hard and while emphasizing small and near unhearable details, some distinct hi-freq sounds are messed up... of course is not a bad CD rip, I don't have this problem on other devices. So it works unpredictably, I hope a firmware update may fix this.
UPDATE : Installed new firmware, now plays everything perfect. Probably before had a somehow corrupted old firmware.