Amazon Fire TV Stick 4K review: This is the media streamer to beat

The Fire TV Stick 4K is the media streamer that Amazon should have released years ago. Cooler than a Roku and much cheaper than an Apple TV, the new $50 streaming dongle offers 4K HDR video in every conceivable format while outperforming Amazon’s more expensive Fire TV Cube ($120) and third-generation Fire TV ($70, now