I recently upgraded to the MkIII and at the same time purchased an output mod which replaced the capacitors with a DC coupling circut (designed and installed by a former SF designer). The improvement in sound is quite amazing, especially on acoustic instruments where timbre, tonal balance, dynamics, etc. are so important. The upgrade significantly increased the amount of information passing through to the speakers -- bringing along the room acoustics of the recording studio, better preserving the harmonic structure of each instrument, and overall making the sound seem more analog than digital (e.g., fuller and less etched). The sound also seems clearer and more detailed. I'm finding I appreciate the upgrade more and more with time.
