Well, I can address the technical aspects of that review (and leave the listening impressions parts to the imagination 
)
For starters, the bulk of the technical benefits described in that review revolves around the EtherREGENās āADIMā (Active Differential Isolation Moat) feature, with the circuit board separation, isolation, etc.
The fact is, that exact same thing can be achieved with just a pair of $25 Optical media converters - 100% electrical, galvanic, and, noise isolation - with the added benefit of not having to replace (or add to) any existing Router or Switch at home.
And then thereās a brief mention about āhot-roddingā the EtherREGEN with a 10MHz external clock input.
Well, the EtherREGEN uses the Microchip Gigabit Ethernet Switch chip (KS9897S), which requires a 25MHz clock, not 10MHz. So, that ultra precise external 10MHz clock input (that some folks connect to a multi-$1,000 Rubidium Atomic Clock), has to get multiplied/divided by a $20 Silicon Labs clock generator chip (Si5340B), dramatically negating any supposed āphase-noise reductionā properties of the EtherREGEN 
The reality is, even a $50 Ethernet switch with built-in crystal will reproduce 100% phase-noise-free accurate packets that have zero consequences on music reproduction.
If you look beyond that review, the Uptone folks also wax lyrical about the Ethernet PHY in their white paper. Turns out the EtherREGEN uses a common off-the-shelf discrete Texas Instruments Ethernet PHY chip (DP83869HM) for the SFP and āBā ports, while the āAā ports use the free built-in PHYs on the Microchip. Absolutely nothing out of the ordinary.
Bottom line, everything that that $640 achieves technically, can be had for about $100-150. And if anyone is wondering, yes, Iāve tested and still own an EtherREGEN that remains unused.