I had a full day of testing yesterday. In 65% of the songs, we preferred the Roon Renderer (with GigaFoil/Keces). In 35% of the songs we preferred the Pro USB (with GigaFoil/Keces feeding either the Nucleus + or the Aurender N10). We tried multiple USB cables as well: Curious, WW Platinum 7, Synergistic Research (some new top of the line Ted gave me) and a few others.
It’s a great product for those who still want to use a USB player in their system and may not necessarily like Roon. But in my opinion, it introduces the characteristic of three different cable types into the mix: Ethernet, Fiber, USB. Backgrounds did sound blacker with the Pro USB. I think. The issue was that they were both so close in sound, there cannot be a clear cut winner. Each had very subtle characteristics and benefits.
It is certainly on par with the Roon Renderer. For the store, I will be sticking with the Roon Renderer for simplicity sake.
Personally, I would love to see a Ethernet to Pro ISL box (even if it would require power). Just my two cents.
But in the end, it’s another great product from MSB and further lending to the benefits of a modular system.