Unforgiving is another of those words poorly used to describe audio. It means nothing. If it is intended to mean that it reveals nuances in the performance of components upstream in the system, then that is how it should be termed.
As I said earlier, I own both of these amps and have immediate and present experience with both, in my home, in my system. To me, the Krell presents a less colored version of the recorded performance than does the MF. The MF has what I hear as a mid bass bump that adds what some might term "warmth." My personal preference is to hear recordings the way they turned out, and to able to separate the "wheat from the chaff." Many recordings do not sound good primarily because they were poorly produced. The last thing I want is a system that artificially colors the music in a way that does not let me hear it as intended, for better or worse. Others may desire such artifical coloring to try and "hide" blemished production values and I respect that. To me, such an approach eventually becomes fatiguing. But the Krell is no more "forgiving" of music than the MF, which simply colors it more so as to provide what I perceive as artificial warmth in this quite audible portion of the frequency spectrum. Some may desire this.
By the way I listen to vinyl 50% of the time and have an EAR834P phono pre that "warms" up the vinyl presentation. Again the Krell provides an "auditory view" into this setup that is accurate; I wouldn't have it any other way.
Also I listen to jazz, rock, classical, electronica and I have always maintained that any system should be able to play back all styles equally well. Otherwise there is something askance and will eventually lead to disatisfaction.
