Thanks to the OP for the post. I had been considering a Node but based on the information in this thread I'll probably go another direction.
Regarding the high rating on Amazon, I take that with a grain of salt because most people leave their rating fairly soon after receiving and installing their product. It it tends to work OK for the first few months and then breaks down very few people go back and leave another rating.
I don't know what percentage of Nodes are failing but apparently it's enough so that there are known issues. It doesn't appear that Bluesound is taking it seriously as far as I can tell.
The biggest issue to me is the poor customer service. If the unit is not functioning properly it should be replaced with a new unit. It's probably unusual that the OP got two defective units in a row but odds are it's going to happen once in a while.
I always take complaints about a particular product with a healthy dose of skepticism but this one seems to have good credibility.