This device is excellent.
I had a little trouble installing the computer interface because the Sigma in my application is going to a router which has Focusrite RedNet, a C|24 console and some other things on it already.
The Sigma is controlled through a webpage. Read more
Once I had the conflicts etc. sorted out, operation was very straight forward.
I downloaded some songs in my session at 96kHz and listened back in pure AES digital and analogue summed through the SSL. In both cases the signal went to a Grace Design preamp and straight to Genelec 8050s. After numerous blind listening test by myself and others - the SSL sound was preferred over pure digital every time.
Its just a little rounder and leaves a mix more defined with less clutter.
The Sigma signal was actually a little hotter than the digital so we matched levels. Working flawlessly as advertised.
All in all - amazing. I am now mixing through a state of the art SSL using my DAW.