Samsung is one of the biggest electronics companies worldwide, and besides producing TVs, you can easily find Samsung phones, soundbars, monitors, home appliances, and other products. Even though they've started producing OLED mobile phones, they have yet to make any OLED TVs, but their QLED TVs are a great alternative for people who don't like the risk of permanent burn-in associated with OLEDs.
Samsung has made improvements in terms of gaming performance for their TVs in the last few years. They normally have low input lag, and their higher-end models have a 120Hz refresh rate with FreeSync variable refresh rate support to reduce screen tearing, which should please serious gamers. Samsung uses TizenOS as their smart interface, which is user-friendly and has a ton of apps available to download.
LG was one of the first companies to produce OLED TVs, which are revolutionary because they're different from classic LED TVs. OLEDs can individually turn off pixels, so they're able to display a perfect contrast ratio and black uniformity, and subtitles are displayed perfectly, too.
Besides LG's flagship OLED TVs, they also produce cheaper LED TVs in their Nano Cell series. Most of these TVs have IPS panels, which have wide viewing angles at the cost of its contrast ratio. Still, the LG NANO85 and the LG SM9500 have some of the best native contrast we've seen on an IPS TV so far.
Sony is one of the most well-known electronic companies worldwide, and their products aren't just limited to TVs. They make cameras, soundbars, headphones, Blu-ray players, and PlayStations, to name a few. Even though their TVs are a bit more expensive than their competitors, Sony TVs are generally well-built and they have exceptional quality control too, so you know that what you order shouldn't have any issues.
Sony TVs are known for their color accuracy, as even their lower-end TVs, like the Sony X800H, have excellent color accuracy out-of-the-box. For many years, Sony has been behind Samsung in terms of gaming performance, as their TVs' input lag is a bit too high and they don't have support for any VRR technology just yet. The Sony X900H should be getting FreeSync support in a future firmware update, which should please serious gamers.
Vizio is a growing American company that's relatively young compared to some of the other big-name companies, as it was founded in 2002. They went from making budget TVs to higher-end models to compete with Sony, LG, and Samsung, and the Vizio P Series Quantum X 2019 is one of the better TVs on the market. Since TVs are Vizio's main product, they can focus on improving them, but they've expanded into making soundbars and speakers. Vizio favors using VA panels for their TVs, so naturally, they have better dark room performance at the cost of good viewing angles.
TCL is a Chinese electronics company that makes TVs, mobile phones, air conditioners, and other electronics products. They haven't been making TVs for very long and they have quite a limited lineup, but their TVs are good budget-friendly choices. In the United States, their TVs come with built-in Roku operating system, which is easy to use and has a great selection of apps available to download.
According to rtings.com