I’ve learned through my sources at Amazon that the voice remotes that are included with the new Fire TV and the new Fire TV Stick bundle are slightly different. The two remotes are functionally the same but are made up of slightly different materials. I’m told the Fire TV’s voice remote is slightly more premium than the Fire TV Stick’s voice remote, but it’s unclear in what sense exactly. This was done to reduce the production cost of the Fire TV Stick bundle in order to keep it under $50.
Both of these remotes connect to Fire TV devices through wifi and will be backwards compatible with existing 1st-gen Fire TVs and Fire TV Sticks once those devices receive Fire OS 5. Amazon is still selling the 1st generation bluetooth voice remote, but they have not listed the 2nd generation voice remote for sale separately. It’s unlikely that Amazon will sell, or even acknowledge, two different 2nd-gen voice remotes. I speculate that once the stock of 1st-gen voice remotes is depleted, Amazon will simply begin selling 2nd-gen voice remotes in its place.