I would not waste time with either of those since I have an
Android sat receiver that does more than Roku and Fire combined.
If I was limited in options and had to get a "sheep" type streamer (Fire or Roku) hands down I'd get the Fire. It runs Android. Even without Google Play store I could still choose to sideload tens of thousands of Apps on it including Vudu but more important XBMC. In comparison Roku is extremely limited. You get their Apps and perhaps a handful of private channels or whatever they are called made by a very limited pool of developers.