I've used many of these USB-to-S/PDIF converters over the past 4 years. I like the concept of asynchronous USB, and I also like being able to change my USB converter as technology changes, but keeping my Aurender server, sort of like changing cartridges on a turntable. Over the past 4 years, I've used a Berkeley Alpha USB, the Lampizator USB Transport, the Mutec, a Singxer F-1, and now the Eitr. They were all excellent sounding interfaces, but the processing capabilities of these devices keeps advancing, and prices keep falling.
I sold the Mutec this week....
Dave