Since the original 500's release I have never seen a single forum post (in generic tech discussions) about the product.

In other words, for me who spends lots of timing reading/watching discussions/reviews of gadgets, this never came up once, anecdotally.

I don't think you are alone in your confusion.

One has been sitting in my hallway closet running a pretty complex HA setup. It has been so rock solid that I more or less forgot about it.