I've found that when it comes to DACs, I prefer the basic, non-upsampling mode. Anything else sounds too etched or sharper than normal and not real. The only analogy I can think of is tracing a beautiful picture hundreds of thousands of times. It will look like the original and then, nothing like the original.
It will have lines all its own and though resembling the original it simply will not fool anyone. That's not to say it will look bad, just different, and maybe even pleasing to someone. I also wonder if all of this upsampling to the nth degree is like the old horsepower wars of old: the more, the better, or so we old timers thought. High Rez downloads might benefit from upsampling but to me ears, via coax from my DVD player to my Music Hall DAC, the basic setting is all I need (but it does oversample 8X).
Just like separates tend to sound better by virtue of the thought and dedication it takes to fully implement them, maybe, just by separating the DAC from the transport allows designers to do the same and build a DAC with better parts without the size and constraints of a CDP.
Or I'm just whistling Dixie.
Either way, I feel that my Music Hall is just a well built DAC that does what it needs to and lets me sit back and enjoy the music.
Sorry about the long intro, but I'd like to hear what others feel about this.