Many smart TV platforms are less than perfect, so you're almost always better off adding some kind of streaming device. Now Roku is cutting out the middleman completely, by releasing TVs with Roku baked right inside. Synergy!
There are two OEMs making Roku TV, TCL and Hisense. The TCL sets go on sale today via Amazon—it's $230 for the 32 inch set, $330 for the 40 inch, $500 for 48, and $650 for 55. All of the TCL sets are high-def 1080p with 120Hz refresh rates. Hisense Roku TVs will go on sale in the end of September. They come in 40-, 48-, 50-, and 55-inch models, at several different big box retailers. The bigger two models are 1080p with 120Hz refresh rates, and the smaller two are 1080p with 60Hz refresh, i.e. these are the bargain guys, especially when you consider the small catch—Hisense is letting stores set their own price (meaning, no MSRP), and those have yet to be announced.
Anyway, if you're at all familiar with Roku, the experience is the same as the streaming platform you know and love on Roku 3 or the Roku streaming stick. Which is to say a very good streaming platform, with more than a thousand of channels that you want (HBO, Showtime, Amazon, Netflix, Vudu, et al) and many that you don't (think fundamentalist evangelical content). There's something for everyone! It's easy to navigate back and forth from the Roku platform to your regular TV—Roku TV comes with a really basic remote, not unlike the existing Roku remotes, that you can use to flip from cable to your DVD player to Roku TV. You can also control Roku TV from the Roku iPhone or iOS app, if that's more your bag. In terms of speed, they're no match for Amazon Fire TV, but Roku TV seemed pretty fast when I saw it demoed in a New York press briefing.
So really, there's not all that much to explain about the experience. It's pretty much Roku pre-installed on a TV. The best ideas are always pretty simple.