New technology often takes a pretty serious beating on Amazon. I suspect that most of those who buy stuff through Amazon early in the release cycle aren't doing their due diligence.
Equipment that has been out for a year or more is usually rated much better as evidenced by the 4+ star rating on conventional HD boxes from DISH and DIRECTV.
I suspect that many of the complaints about the 2.5 star Genie and the 1.5 star Hopper also have to do with not understanding what's going on -- like the poor soul who was expecting an unsurpassed VOD experience.