I am using an older version of this, it sounds surprisingly good. The only thing well known that I've compared it to is a Wadia 121.... My Dac was richer, more organic with similar detail and sound stage.... But, what I have has an inferior USB decoder and I am using an Audio GD USB to Spdif. This is a very good value.
http://www.ebay.com/itm/Valab-ES9018-Sabre-Asynchronous-32bit-192K-USB-DAC-with-XLR-Balanced-Output-/251299941940?pt=US_CD_Players_Recorders&hash=item3a82a4ce34
http://www.ebay.com/itm/Valab-ES9018-Sabre-Asynchronous-32bit-192K-USB-DAC-with-XLR-Balanced-Output-/251299941940?pt=US_CD_Players_Recorders&hash=item3a82a4ce34