As of April 2007, DRM-free iTunes songs are 256kbps AAC. Amazon MP3 is 320kbps MP3. Audio file formats are a highly-debated and subjective matter, but the conse

As of April 2007, DRM-free iTunes songs are 256kbps AAC. Amazon MP3 is 320kbps MP3. Audio file formats are a highly-debated and subjective matter, but the consensus seems to be that “AAC is higher quality at the same bit rate, so you can use a smaller file to achieve the same quality as MP3” [1]. (Originally DRM-free songs on iTunes cost extra, but now they are the default.) [1] http://www.planetofsoundonline.com/articles/compression1.html http://www.planetofsoundonline.com/articles/compression1.htm...