Those of us who have one may have jumped the gun to some extent: MDAC2 will have proper USB isolation, so the effect of the Regen should be that much less noticeable.
It may be splitting hairs, but I see it not as a 'DAC improver' but a 'source filter'. I am constantly trying to make a laptop based system (FLACs on JRiver, internet radio & YouTube) sound as sweet and natural as my FM Tuner/amp/speakers upstairs. With the arrival of the Regen, I'm a couple of steps closer: the 'digital edge' (jitter) I'm chipping away at is very nearly gone, and I believe MDAC2 + linear psu, will finish the job.
So imo: it's not snake oil, the problem the Regen seeks to address does actually exist; JohnW is already tackling the same issue, but from a different angle; I decided the Regen was cheap enough to be worth a try, on the basis that however good the DAC, the cleaner the signal fed to it the better.
(Happy to let John examine it, but guessing that's likely to be some time in 2016......)