This thread is 14 years old and a lot has changed in Class D since then. My AGD Duets Class D have excellent imaging and soundstage, and they compare well to my Boulder 866 and Pass INT-25 (with Playback Designs MPS-8/MPS-X DAC/streamer and YG Hailey 2.2 speakers).
It would depend on the type of music I'm listening to, but at moderate sound levels, I might rank them as Pass INT-25 > AGD Duets > Boulder 866, but all 3 are excellent. At louder sound levels, AGD Duets > Boulder 866. With the AGD's I use the PBD DAC variable volume control with balanced interconnects direct to the AGD amps.