I bought one of these recently, on basis of recommendations (web and friends) and had the opportunity to try it out the last couple of days.
First a couple of words about my system. The digital chain is QNAP server going through a couple of network switches then ethernet to Uptone Ultrarendu going into the USB port of the Playback Designs MPT-8 transport, which is connected to the MPD-8 DAC using optical cable and the special ports reserved for this on both the transport and DAC. This offers full galvanic separation to the DAC.
Using bog standard ethernet cables, I could not detect much difference if any with the etherregen in or out. If I had to decide, I preferred the sound without the ether regen in the system, though having said it was difficult to hear differences.
I substituted the cable going from the Ether regen to the Ultrarendu with a $100 ethernet cable (DH Labs) and things improved. It definitely sounded better than with the $3 cable, not a huge difference, but better.
Did it sound better than the direct connection using a $3 cable? Maybe, I’m not sure but I’ve currently kept the Ether regen in using this configuration and will use it for a month or so before testing again.
Of course, I am now intrigued about the cable effect. I’m keen to try an ‘audiophile’ cable directly into the Ultrarendu fro the wall - the one I have is not long enough.
I am also curious to try the Ether regen in a less sophisticated system to see if that would bring in a substantial difference.