Well I've recently purchased a portable DAC/headphone amp (I also use it at home with my PC) and overall I've been quite happy with the performance of the unit I know that typically the FLACs I've ripped sound better than the 256kbps mp3 files that Amazon has available. I thought I was going to be using HDTunes as my source for FLAC downloads but since they can't even send me a link to download their test album that they promote for free I'm not terribly confident on purchases from them. Do you folks have any recommendations on sites for FLAC purchases that are reputable and have a pretty good variety of music in their catalog?