Consumer Reports wonders whether hi-res audio is worth paying for.
According to Consumer Reports’ testers, though, the differences between hi-res audio and CD, high-quality MP3, and high-quality AAC files are less distinct to the ear than one might expect, even on the very high-end audio system in our labs. “If you notice any differences at all, they will only be in the very fine details of audio and only if you are paying close attention,” says Maurice Wynn, our resident audio expert. "We also found that the differences were less noticeable when listening through headphones.”
UPDATE: for the TL;DR crowd, the “tests” were done prior to April 2015, they only tested three portable music players playing unspecified “high-res” tracks compared with an Apple iPod playing 16/44.1 WAV and 256K AAC versions of the tracks, only with what the Roon crowd would probably consider down-market headphones and an unspecified “high-quality audio system”, and the expert listeners could indeed tell the difference between compressed and uncompressed when using the highest-end headphones. Not much of a test, IMO.