Like cat videos and Kardashians, smart TVs seem to be everywhere. According to market research firm Quixel Research, they'll represent close to 60 percent of the TVs sold this year, marking the first time sales of Internet TVs will outpace those of nonconnected sets.

All smart TVs offer online access, using either a wired Ethernet connection or Wi-Fi, to get additional content such as streaming TV shows and movies from Amazon Prime, Netflix, and other services. Some smart TVs are limited to popular streaming video and music services, while others offer apps for games, social media, and news and weather services. Many offer a browser, though surfing the Web hasn't proved to be an especially satisfying experience on most sets.

The more sophisticated smart TVs can respond to voice commands, make program recommendations, and swap content with your smart phone.

There isn’t a single smart TV standard. LG and Samsung use proprietary platforms, while Panasonic and Sony rely on open operating systems such as Mozilla Firefox and Google Android TV. There are even "Roku TVs" from Insignia, JVC, Hisense, and TCL that bake the streaming player’s software right into the set.

Here’s a quick look at the smart TV systems used by four top brands.

LG: webOS 2.0

WebOS, acquired from Hewlett-Packard, is among our favorite platforms. The main menu features a row of colorful, semi-transparent cards, or tiles, layered across the bottom of the home screen, so you can watch what you like without interruption. An amusing setup animation helps you get started, and the homepage is customizable, so you can add, reorder, or delete app cards to suit your preference. The whole system is fast and responsive, and LG’s Nintendo Wii–like point-and-click Magic Remote has long set the standard for these types of remotes.

Samsung: Tizen

Originally developed for smartphones and watches, the Samsung Tizen system reminds us more than a little of LG’s webOS. Tizen also uses a row of colorful cards arranged across the bottom of the screen to provide quick access to recently visited apps and channels, perform searches, and browse the Web. Like LG, Samsung has a motion-activated point-and-click remote control, though to operate the onscreen cursor you have to touch the pointer button—a useful feature since you're less likely to accidentally summon that cursor. The remote also has fewer buttons than LG's, which can sometimes make it more difficult to perform some functions.

Sony: Android TV

Despite the failure of Google TV, Sony is once again partnering with the search giant this year, adopting its successor, Android TV (shown in the image at the top of the page), as its smart TV platform. Compared to the streamlined systems used by LG and Samsung, Android TV seems overcomplicated and almost bloated. The setup is clunkier—you need a Google account and plenty of patience when the firmware is updating—and the main screen features seven rows of cards, only four of which appear at a time. Even worse, the most useful row, Apps, is the fourth one down, and you can’t reorder the menu. On the plus side, Android TV's voice recognition performs well if the set you buy comes with Sony's secondary remote. The platform also supports Google Cast, which lets you send content from a phone or tablet, though it works better with—no surprise—Android devices than with Apple phones and tablets.

Panasonic: Mozilla Firefox

Panasonic surprised everyone this year when it adopted Mozilla’s Firefox as the operating system for its smart TVs. While the new platform is visually more appealing than Viera Connect, functionally it doesn't do much to raise the bar. The setup is easy, thanks to an animated wizard, and the interface, which opts for bubble-style icons rather than tiles, and is sleeker and less complicated. We also like the universal search function, which includes streaming, live TV, and personal content stored on a USB drive or home network. The platform works well with both Android and Apple devices, too. But Panasonic seems to offer fewer apps than its competitors—even though most of the major ones are there.

Although most TVs, especially the larger-sized sets, now come with built-in access to online content, you can always add that capability with a streaming media player. We recently posted reports on several options, including a new Apple TV, a new Google Chromecast, and a revamped Amazon Fire TV.

We'll be doing first-look evaluations of those players soon, and once they're fully tested, we'll add them to our comprehensive streaming media player Ratings.

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