I recently upgraded from the Sonore opticalRendu and paused to question my own sanity given the increased spend. I thoroughly enjoyed the opticalRendu for over a year and would highly recommend any Sonore solutions as an entry into the streaming market. While a comparison was not performed with the ultraRendu I can praise the optical connection for ultra clear signal. Those craving CD quality and above should implement this connectivity in your system.
The Signature Rendu is absolutely amazing in its clarity, detail and simplicity. It is the powerhouse that you often read about in other technical reviews. The optical USB input port is very convenient and eliminates an extra converter and cable expense. Same with the internal power supply. For those contemplating whether an external power supply would provide better performance, I did not find this to be the case when upgrading. In terms of the sound, it is a night and day difference between the two Rendus. The Signature Rendu is far superior than the opticalRendu. It is similar to the difference between listening to a band’s recordings and seeing them in concert. I can assure those who are also questioning whether the upgrade is worth the additional expense, it is for sure. I would not hesitate in making the same decision again if it should arise.