Grannyring,
My 2.0nB was modified to reflect the 2.1 changes. I perceive the result as improving the articulateness of the soundstage.
In my system, the soundstage became deeper and the instrument positions more precise. Voices became more relaxed, natural.
I associate these improvements with the positive characteristics of tube signal handling. Other (negative) characteristics associated with tubes - loss of bass control, noisier signal - did not appear with the modification.
Both my preamp and my tube DAC received the new capacitors. I think the more significant improvement came to the pre-amp