You are going to have an impossible time finding someone who heard all three as they play in VERY different price points, the PSA PWD being the high priced anomaly. There are dozens of reviews, user and professional, about the PWD. And spending any decent monies on a USB DAC brings up the obvious next question....why iTunes when there are much better sounding software players, many that use iTunes as a GUI and library (Pure Music, Bit Perfect, Amarra, etc)?