(Disclosure, I may receive a small referral fee when you make a purchase through links on this post.)
Users are not happy with Amazon as the voice recognition software prefers its own content and only supports Vevo content (verified by reviews on its own website). It doesn’t appear to work with Hulu or Netflix. One of the major feature of Fire TV is the ability to use voice search. However, when you search for a video, only content to purchase will be displayed even though it may be free on other apps such as Hulu or Netflix.