The Good: Better streaming format support than anything in its price range. Voice features are best-in-class, and Echo and Dot owners can control it with Alexa. Its app and game selection is superb, responses are lightning fast and video quality is as good as any streamer. The remote can control volume and power on TVs and sound bars. The Bad: The user interface pushes Amazon content too aggressively. The selection of 4K, HDR and Dolby Vision TV shows and movies is worse than on Apple TV 4K or Roku. The Bottom Line: It flogs Amazon content too much to beat Roku, but for Alexa fans or 4K HDR TV owners who insist on Dolby Vision, the Fire TV 4K Stick is a great value. Hey TV owner, are you annoyed by your set's streaming and "smart" features? There's a cheap fix for that.Get a media streamer that serves up Netflix, Amazon Video, Hulu, HBO, DirecTV Now, ESPN and all the rest in a package that puts most smart TVs to shame. If you have a TV that handles 4K resolution and high-dynamic range video, you should get a 4K HDR streamer to take advantage of your TV's best video capabilities.By that logic, if your TV supports Dolby Vision HDR, you should get a Dolby Vision streamer, right? Alas, as with most things that have to do with HDR on TVs, it's more complex than that. The Amazon Fire TV Stick 4K is the cheapest streamer that supports Dolby Vision, one of a handful of HDR formats. In fact it's the only one, aside from the Apple TV 4K, which costs more than three times as much. But that doesn't mean everybody with a Dolby Vision-capable TV should go out and get a Fire TV Stick 4K.One reason is because on most TVs I've tested, Dolby Vision doesn't provide much, if any, image quality boost over "regular" HDR (also known as HDR10), which is available on plenty of competing streamers, including Roku. Another is that, beyond Netflix, there just isn't much to watch in Dolby Vision on the Fire TV 4K right now. Apple's iTunes store has a bigger selection of 4K HDR movies than Amazon, as does the Vudu store available on Roku.A nice Fire TV upgrade, but Roku still winsAmazon's Fire TV 4K's best feature isn't Dolby Vision, it's Alexa, which lets you use the included voice remote or a paired Echo speaker to control video playback, launch apps and, yes, check the weather with just your voice. The Fire TV's chief competitor Roku works with Google Assistant now so the voice gap is narrower than before, but Assistant on Roku isn't as capable as Alexa yet, and can't control Netflix.If you don't care about Dolby Vision or controlling TV hands-free with your voice, the Roku Streaming Stick Plus is still a better choice than the Fire TV Stick 4K, even though it's $10 more. The main reason is Roku's interface, which puts all apps on an equal footing. Fire TV's menus are more modern-looking, but they steer you toward Amazon's stuff. You can't use Fire TV without experiencing a screen full of Amazon videos and promotions everywhere you look. Both the Fire TV Stick 4K and Roku Streaming Stick Plus can control your TV's volume and power, load apps lightning fast and run circles around the built-in app suites on most 4K TVs. Among sub-$100 competitors they also trounce Google Chromecast Ultra, which doesn't have a separate remote or Amazon Video, rendering it a distant third place in my book. The choice between the two, at least for folks unwilling to fork over for an Apple TV 4K or Nvidia Shield, boils down to a choice between voice features and Dolby Vision (Amazon) or a neutral interface (Roku). In my opinion Roku still wins, although this year the race is closer than ever.The Big Sick, er, I mean 'Stick'Although smaller than the 2017 Fire TV "pendant" it replaces, the Fire TV Stick 4K is huge for a streaming stick. It's about double the size of Roku's sticks, but it's still designed to hide behind your TV out of sight thanks to the attached HDMI port. Amazon includes a little "port saver" to allow the bulky stick to attach to crowded rear panels.You can get 4K HDR and Dolby Vision video for the Fire TV is from Netflix and Amazon itself, while YouTube can play in 4K HDR (not Dolby Vision). Roku lacks DV but has more selection, including those three as well as Vudu and FandangoNow in 4K HDR.Streaming in 4K requires more bandwidth and, in the case of Netflix, a more expensive plan. Amazon recommends 15Mbps as ample for 4K streaming, while YouTube and Netflix recommend 20.Aside from 4K HDR, the only major advantage over the standard Fire TV Stick is a faster processor. The standard stick is plenty fast in my experience, however, so don't expect the 4K version to be that much faster.Fire TV is the only major platform that doesn't support YouTube TV, one of our favorite cord-cutter streaming services. Otherwise its app selection is almost as good as Roku's, albeit without as much of an accent on free ad-supported shows.TV control: Easy setup, more options than RokuAmazon "borrowed" a page from Roku by adding the option to control your TV's volume, mute and power with dedicated buttons on the remote. I love that feature on Roku's devices, such as its Streaming Stick Plus, because it allows you to pretty much ditch your TV's clicker. On the TVs I tried from LG, Samsung, Sony and Vizio the Fire TV's remote worked perfectly, automatically detecting my TV type and programming the remote accordingly. All I had to do was confirm it worked. The one exception was the Sony TV, which it detected as a Samsung. The setup menus made it easy to correct and once I'd specified I was using the Sony, everything worked perfectly.In addition to Mute, a button Roku's clickers lack, the Fire TV goes one better with more control options. If you have a sound bar, you can set up the remote's volume and mute keys to control it instead (while the remote's power button still controls TVs). It worked well with a Vizio sound bar I tried.Voice control opens up even more options. You can change volume via voice (complete with the ability to specify volume increments), turn the TV on and off (although I couldn't get this last function to work correctly), or even switch TV inputs to another device. It's like a "lite" version of the voice controls available on the Fire TV Cube, except it uses infrared commands sent from the remote. Amazon sells the new remote separately for $30 (\u00a330), so you can use that sweet TV control on older Fire TV devices.Va-va voiceVoice control with Alexa and an Echo Dot worked well, just like I found on other Fire TV devices. Launching Amazon shows was as simple as saying, "Alexa, play Jack Ryan," and most searches for non-Amazon shows returned relevant results. Commands such as "Home" and "Launch Netflix" worked as expected, and I didn't have to use cumbersome phrasing like adding "...on Fire TV" to the end of commands. Searches for specific shows worked on Netflix, as long as (as usual) I was exact in my phrasing. "Play Sabrina the Witch on Netflix" played Sabrina: The Teenage Witch on Hulu, not The Chilling Adventures of Sabrina on Netflix. My bad, I guess.Voice support on Hulu worked particularly well, including support for commands like play, pause, stop, rewind and so on, as well as "tune to ESPN" to get live TV. Movies Anywhere also worked well with voice commands. Amazon says voice controls are coming to more apps, including A&E, AMC, Sony Crackle, Hallmark Movies Now, HBO Now, History, IFC, Lifetime and VH1.