Al Schmitt, Grammy award winnig Sound Engineer, loves the AK100. See his interview on YouTube for his impression of the Astell and Kern studio sound AK100 v. MP3 options: http://www.youtube.com/watch?v=0XMTFwqB6jI
You may also wish to check out other YouTube vids regarding the AK100 player:
http://www.youtube.com/watch?v=hFiZgiKBQJg
http://www.youtube.com/watch?v=Fx8pGAne_2Y