I work for an electronics retailer, and we use Node130s in ten separate demo displays which have been playing day in and out (pretty much 12 hours a day) since the product was released. Before the 130, we used the 2i in all of those locations. Never had as much as a hiccup. I can also report that based on returns/service reports, the number of issues with the product is lower than any other streaming device we carry with the exception of Auralic (by percentage).
@jjss49 made an excellent point; people generally don't post online to say "this works well" or "no problems here" so the majority of customer reviews will be folks with an axe to grind, which makes it appear there are "nothing but problems" with the product in question. This happens with literally every brand and model, be it electronics or appliances. My favorite is argument along the lines of "I had a walkman fail when I was in high school so I'll never buy another Sony product".
This is not to make light of your issue, I would be frustrated too, and the $75.00 off for a refurbished unit does seem a little stingy.
Regarding the NAD power supply, Lenbrook is the parent company who owns BlueSound, NAD, PSB, and Dali brands, and many of those products use the BluOs platform.