In any generation of Roku devices, there's always a "top of the line" device that works better than the others. Other devices in any generation may work well, but one is always considered the best, usually by the processor, the onboard RAM, the video, or other features. But there's always one top dog.
You didn't say which Roku you have, so we're shooting in the dark here. Note that if you don't have any of the devices I'm about the list, then understand that you'll likely get an improvement if you got a different device at the time you got yours, meaning yes, you would get an improvement today.
In the early years, there was one device in 2008. In 2009, the Roku XD-HR was top of the line, then in 2010, the Roku XDS was top dog.
That spot then went to Roku 2 XS in 2011, before the introduction of the Roku 3 in 2013. Hardware issues kept the Roku 4 from being considered the best in 2015, which most picing the updated Roku 3 as best device to get.
In 2016 came the Ultra. That model name has been updated a few times, and the Ultra remains the top device today.
Today's low end devices perform on par with the Roku 3 in responsiveness, if not a little better. And to long time Roku users, that's saying something, as the Roku 3 was beloved by many.
As for which is the best to get, the simple answer is to get the top of the line device. However, depending on which features are important to you, a cheaper device may be the best choice for you. Many users are high on the Roku Express 4K+ (model 3941). I have no personal experience with it.
Ultra is top of the line? It might be the most expensive but the Ultra is defective. We are on our second unit and this one has also failed. Roku support has hung us out to dry even though we are still in the warranty period. Support doesn't have a clue what they are doing, at least now. They seem to have gone downhill very fast in the last few months. It's time for a different brand! They have severely upset me with their ineptitude and failure to perform for me as a customer.
Nah it's not worth the aggravation. The ultra is going in the trash once I get something to replace it. I most certainly am not paying to ship it back as that would be throwing money away just to receive another defective unit and I would have to buy something to use in the meantime anyway. First time they sent me the replacement up front and now they won't even communicate with me. I'm done. Roku as a company really sucks.
Update - I changed the suggested settings from another thread in the ultra with no improvement so I switched to a tivo stream 4k which performed flawlessly for quite some time. Don't care for the format though. Then, I got a new tv. It's a Sony X85J. Also got a new Roku Ultra. After a month and a half the new Ultra started doing the same thing on the new tv - that same pixelated multi colored screen and then a reboot.. I couldn't believe it. Only done it once so far but that's enough to be totally displeased with the Ultra. Never had a lick of trouble with the sticks. This is the third Ultra to have this same issue! Pic is of old TV but the same issue happens with the new setup.
We would be more than happy to look into this issue for you.
Can you please provide us the following information:
-Roku device model, serial number, device ID, and software OS/version (these can all be found in Settings > System > About)
-TV brand and model number
-steps to reproduce the issue you are seeing
Once we have this information, we will be able to pass it along to the appropriate Roku team to investigate further.
I've been this troubleshooting route before. Supplied all the info asked for. Get different answers each time for the same issue from some terribly unprofessional staff. This keeps happening with each Ultra I try.... 3 so far. One was an older Panasonic tv the other is a brand new Sony. I have done all the suggested adjustments to no avail so I got a new TV and a new Ultra and got the same result.Same issue every time. I don't know the answer here.... I like the Roku format above all others that's why I keep trying but this is the third strike so Ultra has struck out. I think a Shield is in my near future but I really don't like the format. But if it works, I guess I will have to live with it. I would expect a full recall of the Ultras in the future. I can't be the only one with this issue!