I just want to know which is better: buying a Roku TV with Roku already built into it, or buying a Roku streaming device to plug into to us TV.
Well, there are pros and cons, but I generally favor having separate devices. And yes, I do have two Roku TVs
With a Roku TV, you have a single remote to control everything, including the volume of an AVR attached via HDMI/ARC. The larger TVs have powerful processors that work quite well.
With a Roku TV, you don't have to worry about a bad HDMI cable, since it's all internal.
With a Roku TV, you don't have a numeric pad on the remote, so you can't go directly to a specific OTA channel. That's very important for some people.
With separate devices, you can have a failure of one device while the other is still functional. And if a newer Roku player with new functionality is released, you don't need to replace the TV to get the new functionality.
With separate devices, you can move the Roku from one TV to another.
I'm sure there's more, but this I think covers the basics pretty well.
I've got 5 roku tvs myself, but I introduced my friend to the roku TV and he is fascinated that he wants to get one. I told him that there are 2 options. If wants to save money and not replace his current TV, he can get the roku player, but if he doesn't care about spending money and replacing his TV, he can get a Roku TV. I came on here to ask so I can let him know what people have to say.
If they watch a lot of OTA television, and that requires changing channels often, I don't recommend a Roku TV because of its lack of direct entry buttons for channel selection. Beyond that, It's great having a single remote.