We're big fans of Roku's streaming platform and Roku's streaming media players, which top our streaming player Ratings. But you may be wondering what we think of Roku TVs, given the growing number of sets that now use the operating system.

Based on two years' worth of testing on nearly a dozen Roku TVs from manufacturers including Haier, Hisense, Insignia, Sharp, and TCL, we'd say they're something of a mixed bag.

Before we get into the specifics, consider this: So far, none of the top-performing brands in our TV Ratings have adopted the Roku platform. LG and Samsung have their own proprietary systems. Sony and Vizio use the Google Android TV or Google Cast platforms. That means the Roku TVs we've tested have come from lesser-known brands, the ones that typically end up in the middle or lower ranks of our Ratings.

What We Like

To start, most of the Roku TVs we've tested are relatively inexpensive compared to the smart TVs from better-known brands. They're easy to set up, too, thanks to an onscreen tutorial that shows you how to use the TV interface and remote control when you turn on the set. And, as of this year, the Roku TV platform supports 4K video.

In fact, everything we like about the Roku platform—a wealth of content options, an easy-to-use interface, and a universal search capability that doesn't favor content from one service over another—is now baked into the TV itself.

And all the devices you have connected to the set—cable box, Blu-ray player, game console—show up as apps on the home screen. That way, you don't have to remember which inputs those devices are connected to, or manually switch between them when you go from your cable box to your Blu-ray player. You just click on the app in the menu and the TV automatically shifts to the appropriate connection.

And unlike when you add a standalone Roku player to a TV, you can now use a single remote to control both devices. Sadly, though, you'll still need a separate one to operate the cable box.

What We Don't Like

The operating system is not ideal as a TV interface. For one, you need to sign into, or set up, a Roku account before you can use the set, just like you do with a Roku player. Once you're logged in, the TV updates its apps, which can often be a lengthy process. And when you turn on the TV, it defaults to the Roku home screen, not live TV as most sets do. To watch any programming, you have to select the appropriate app from the tier of onscreen tiles.

The Roku TVs in our labs also lacked popular features such as local dimming and blur-reduction technology, which are common on many sets. And none of the 4K UHD models offered support for high dynamic range (HDR) or wider color gamuts, the latest 4K TV tech.