Pick a platform
Perhaps the most important choice you need to make is your preferred software: Just like phones and laptops, streaming devices have their own operating systems. So you should choose a platform that fits two criteria: It must play your favorite content and work well with the devices you already own.
For example, if you want to watch shows and movies purchased from iTunes, then you need the only device capable of working with that software: the 4K Apple TV ($150 and up on Amazon). If you're all-in on the Apple ecosystem—you rely on a Mac computer or an iPhone—then you'll want this option. It can also stream videos from Amazon Prime, YouTube, Netflix, and many other third-party services, with the notable exception of Google Play Movies & TV.
Android users, on the other hand, should lean toward devices, such as the 4K Nvidia Shield ($180 and up on Amazon), that run the Android TV operating system. This works best with Android-based video apps, everything from YouTube to Plex, although it can't play your iTunes content. An Android-TV-enabled stick will also sync your playlists and other data from the Google apps you use on other devices.
Google's Chromecast is an interesting case, because unlike the other devices we've mentioned thus far, it doesn't rely on built-in apps. Instead, you beam your music or videos to the device from a phone or laptop. The good news is that virtually every video and audio app on both iOS and Android operating systems—from Hulu to Google Play Music, with only iTunes content unavailable—will work with a Chromecast. Despite this flexibility, Chromecast does work best with the Google ecosystem, because you can control it with a Google Home speaker, using commands like "OK Google, show me Stranger Things on Netflix!"
Similarly, you can pair an Amazon Fire TV stick or box with an Amazon Echo speaker, and that platform also works very well with Prime Video and Amazon Music Unlimited. However, the otherwise excellent 4K Amazon Fire TV box ($50 on Amazon) doesn't have an official app for YouTube. If you want to stream your favorite channels, you'll have to load those videos in a browser instead. In addition, you can't watch content from iTunes or Google Play Movies & TV.
To avoid all of these operating systems, try a more neutral option. A device from Roku, like the Roku Streaming Stick+ ($60 on Amazon) has no bias toward an Apple, Google, or Amazon ecosystem. It can play content from Google, Amazon, YouTube, Netflix, and many others, though it can't work with iTunes.
In general, before you commit to your platform, double-check that you'll be able to run the apps you want on this streaming device. Boxes and dongles regularly add and remove supported apps, depending on the deals that parent companies make with each other. For example, an Amazon Prime Video app only arrived on the Apple TV in the last year. Make sure to check a device's online listing, which should prominently display a list of the apps it allows you to use.
Review the features
As you read through each device's description, keep an eye on the features it offers, particularly the visual ones. Depending on the television or monitor on which you plan to display video, these will be important.
For example, as of this year, most streaming devices brag that they support 4K resolutions. This ability has become the current visual standard, which means you should choose a 4K device to future-proof your purchase. Luckily, most boxes and dongles enable this resolution—only older hardware, like the second-generation Chromecast ($35), lack 4K support. We'd recommend you upgrade to the current top-end version, Chromecast Ultra ($70), to get the higher-resolution option.
Another term you might see is HDR, which stands for High Dynamic Range. This visual feature improves the color range of your picture and provides a better balance between light and dark areas of the image. Although it's not as crucial as 4K, again, your display will look better with this feature. However, for the technology to work properly, you need a streaming device, apps, and TV or monitor that all support HDR.
As you read about these gadgets, you may encounter additional little bonus features. Take the Roku Ultra ($100 on Amazon)—it includes a headphone port on the remote, so you can watch on a bigger screen, but listen without disturbing anyone else. These options vary from device to device, so make sure to study the fine print to find them.
Compare prices and specs
Once you've decided on a platform, you still have to choose a specific device. Many of these hardware makers offer several different products with varying prices. To give you an idea of the range, at $150, the 4K Apple TV is one of the most comprehensive and more expensive choices, while the Amazon Fire TV stick with built-in Alexa voice control ($30 from Amazon) is one of the cheapest.
In general, bigger, more expensive options typically boast faster processors that can support improved features. In the case of Amazon and Roku, pricier models add support for 4K and HDR content. For the two newest Roku devices—the Roku Streaming Stick+ and the Roku Express—other differences include improved wireless range and, on the more expensive Streaming Stick+, support for the premium Dolby Audio standard.
Despite these differences, within each manufacturer's family of devices, you'll get the same TV app support across the board. Gaming apps are another story: Only more expensive boxes with more powerful internal specs, such as the Apple TV and Nvidia Shield, will let you stream all the games you want. Even those may not run high-end PC games, but they do let you play thousands of mobile games on the big screen. That's another reason you might want to pay a little extra.