Without getting too technical, what are our impressions of the new format. As soon as the iTunes was put, I re-ripped some of my favorite CD's for 192 MP3 to 102 AAC. To be honest, I'm not sure of the difference. I've read some posts on other threads that were openly critical of AAC. If it were that much better, I'd happily re-rip everything into AAC (at the same bit-rate) for increased fideltiy, but I'm not sure its there.