I just got the idac and am very impressed so far. I pulls the digital signal direct from the ipod and processes the signal via dac. The output thru USB was as good as other input sources which eliminates the need for a S/pdif converter. There is a good review in Stereophile this month and previously in Absolute Sound. What swayed me over the Rega was the better USB performance, less coloration (according to the reviewers) and the ability to doc the ipod and use a remote.