Forgive me if I'm wrong, but it appears to me that comparisons that have been made are between the NuForce and conventional mid-fi/lower high-end amps. In that case it is not very interesting as conventional amps tend to get better when they are higher priced (not because they are overpriced but because they have larger power supplies, tighter tolerance components etc.). It would be interesting to compare the NuForce and let's say a $8-10,000 US conventional amp. I know this would be unfair, but it remains an interesting comparison. If the NuForce isn't wiped out by the much pricier amp, then it would be very convincing indeed. My own personal experience with an Acoustic Reality (eAR) ICEpower amp (also class D) is that in comparison with the almost 10 times more expensive Accuphase A-50V the eAR is no slouch. That's why I'm not longer convinced of the necessity spending $10-20,000 US (or more) for a conventional poweramp to get good sound.
Chris