I have two Roku 3's (4230x) and don't really have any issues with either unit. Still, I had a chance to pick up the latest Streaming Stick + (3810R) when it was on sale around Black Friday 2019 but haven't opened it yet. Because the Roku 3 is an older device that is no longer sold or supported, I couldn't find a single comparison between the two models. My overall take is that while the Streaming Stick + doesnt have an ethernet port, it is likely faster and has greater wifi range than my Roku 3 - especially if my Roku 3 is connected via wifi rather than ethernet, which is, unfortunately, the case in my apartment. Also, the Streaming Stick + supports 4k, but neither of my TVs are 4k and I have no plan to upgrade anytime soon. Lastly, the Streaming Stick + doesn't support earbuds (I never use mine) and doesn't have MicroSD expansion (not sure how that might effect performance). In the end I'm not sure why I would or would not want to upgrade (downgrade?) to the Streaming Stick +. If it's significantly faster and more responsive and has greater range and a cooler interface, that would probably do it, but I'd love to get some feedback and advice from the community.
Re: Roku 3 (4230X) vs. Streaming Stick 2019 (3810R)
Thank you. Had my timing been better, I might have grabbed an Ultra when it was on sale, rather than the Streaming Stick +. That said, chances are that by the time I'd actually be able to avail of the additional features, a newer model would be available anyway, so perhaps the Streaming Stick + is a smart stop-gap compromise until I require a higher end device. :-)