I remember a friend of mine having a Roku stick a while back, and it was painfully slow to use. Sorta like a cheap smart TV. Just really awkward, the UI was weird, and there was a ton of delay between clicking on something and it loading (not like input lag, but the processor trying to load things). I currently have a Chromecast, but I like the idea of something having a remote. Another friend of mine has the Fire Stick, and it's incredibly streamlined and fast, and the voice controls are awesome...but I don't really want to support Amazon's devices, and I don't want to deal with Prime and their other **bleep** being shoved in my face 24/7. That's why I want to go for a Roku.
Which device would perform well and have the features I need? I don't need 4K, and my TV has an HDMI port.
The current Ultra model is the fastest, but also the most expensive. All of the other Roku's are more or less the same processor speed. I have an older Roku 4 and Express, and both are quite fast with very little lag in response. Newer ones should be even better.
You're gonna get a bunch of different answers because most of us only know the device(s) we own and thus can't give you good comparative information. Also, someone's bad experience may just reflect a sub-par example of an otherwise good product, or on the other end you might get the lucky guy who got a good unit in a product that otherwise has problems, so anecdotal reports can be misleading.
After hanging around here for several months, when I wanted to get my next Roku I made the following observations:
There seemed to be more complaints about the Express model than any others by a substantial margin. But I have no idea whether they really are more prone to problems, or if it's just that they are the lowest priced products in the line, and so there are a lot more of them sold. At the low end of the scale you might also get a preponderance of those who are less electronics savvy and thus may be more prone to setup problems. I decided to avoid this model.
There also seemed to be a high incidence of complaints about the Ultra. This is the highest priced product in the line, so one might expect the fewest sales. But they are also the only one with an Ethernet port so may attract the most purists with higher expectations. As I didn't have handy Ethernet access from my intended location and would be connecting via wifi anyhow, I decided to avoid this model too.
The Streaming Stick + cropped up as a daily deal on one site or another about when I was ready to purchase. It wasn't a model I'd marked off my list and I got it for a pretty good price, so that's what I bought. I've been generally pleased with it. I have had the occasional need to re-establish lost wifi connections, but not so often as to be a real nuisance - maybe once or twice a month max.
The Stick+ seems to be just a touch faster in response than the Streaming Stick (not Plus) on another set, but that could be because it's nearer to my router (?). My several years older Roku 3 (closest to router of all of them) is noticeably slower in response. All are considerably faster than the Roku 2 that I retired when getting the Stick+.
But whichever model you buy, please be extra careful when registering your device to a Roku account. Lots of scammers have figured out how to take advantage of internet browser features/quirks to intercept your linking attempt and hijack the process. When the Roku setup screen tells you to go to roku.com/link in your web browser, you should be able to avoid problems if you enter a more complete https://roku.com/link address. If your browser auto-completes the address while you are typing, make sure it fills the address in correctly. If it takes you to search results instead of directly to the site, be sure you only select a choice that goes to the specified address. However you get there, make absolutely sure you actually go to https://roku.com/link(which will probably forward you to https://my.roku.com/link, that's expected and is okay) -- any other address is bogus.
Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T