Good question. My wish, were I to have one, is that someone with extremely precise measurement equipment would measure the difference in the digital output of a $500 streamer and a $3000 streamer (throw out the very cheap and ultra expensive streamers). This would at least let us know if there is ANY difference in the streams and if this small difference would not be retimed/clock accurately by the DAC. I bet I have heard/read 100 times why expensive streamers sound better, but I have never been presented with any evidence from a scope or other precise measurement equipment.

I don’t care if one is better or worse beyond wanting to buy the one that sounds better. Of course, the best option is to blind test both in your system with your speaker/amp/ears.