Anyone who bought Amazon-anything devices and expect openness is definitely going the wrong path. Amazon has some great devices but it has a pretty strict walled garden environment (which, granted, is kind of pretty) where they are expected to stay. Amazon is somewhat similar if not worse than Apple in this regard.
Yes and no - I bought this box because I wanted one device that did both amazon video and Netflix. Met expectations there.
But I also wanted to be able to use it as a front-end for music stored on my NAS. This is why I was never interested in Roku, might've been interested in the Apple product but don't remember it having Prime support, and kept using my Western Digital Live Plus for as long as I did - the access to files inside the walls is important to me.
By day 2, I had enabled ADB and sideloaded XBMC. Yes, I don't have root, but I have Amazon, Netflix and local files all in one place, which I like a lot.
From what I've seen, on the Fire tablets amazon doesn't block sideloaded apps, or I wouldn't have bought this device. It makes a decent HTPC device for my purposes, though, and is open enough for me. Of course I'd prefer root, but in this instance, not if having root broke the Amazon Video stuff.
My biggest complaint so far is that amazon doesn't give us a preference setting for how much bandwidth the box should allocate to itself. So I needed to do that with my firewall instead.
I'll be interested to see if Amazon makes Prime available for the rumored Google TV box. My guess is they will not. But if they do, and I'm within my return window when the device is fully announced...