I have to say in my experience the bit-depth has a larger impact than the sample-rate. I find going from a 24 or 32 bit 44.1KHz recording to 16bit 44.1KHz has a larger difference than going from 96KHz 24bit to 44.1 24bit.

No comments on noise shaping though? Maybe that isnt a technical term. The DEQ2496 has a button called 'noise shaping', which it says does something to shift distortion from something or other to a much higher, inaudible frequency.