I stopped a while back when the LAT International USB cable sounded best over the Cardas, AQ Carbon, and a Neutral Audio (from Italy). And of course a generic black plastic covered cable. All these are below $200.00.
I hear differences very similar to analog interconnects and speaker cables. So I suspect the components are a factor as with analog cables.
Now I'm curious to try the Callisto and Inakustic USB cables.
One thing good about these threads is people have tried many cables, so it gives us a head start and saves lots of time. I personally would like to keep the dollar amount below 500. Thanks to all who have contributed!