I think the type of software used for compression is very important.I am not an engineer so I do not understand the algorithms but listening to tracks at 256 from iTunes,Emusic and Beatport for instance,Beatport to me is the clear winner. Same goes for Flac.In theory,it should sound the same as a CD or Wav file but depending on the software used,by Pure Music or Amarra or flac to....file conversation systems,they do sound different.You will hear it only on a high end system but it is there.As an example,I bought 2 Robert Rich Archive titles,one from iTunes at 256 and one from Musiczeit in Flac,Flac sounded way better and looking at how long it took to download each,the Flac being three times longer,you know there is information being cut out.Of course,I did not have the original file.