Okay, so, I have a Roku Ultra that I use with my C3. Primarily, it's because the Roku works flawlessly with Alexa and the LG C3 by itself does not -- and my wife likes the convenience of turning on/off, pausing/resuming, etc. via Alexa.
Anyway, I've noticed (or think I've noticed) that the LG apps, at least in some services (say, Netflix) produce better quality than the equivalent Roku apps. I've checked and made sure the same settings are applying for each input, and that the Roku Ultra is properly supporting Dolby Vision. It's primarily in HDR that I (maybe) can tell a difference.
Does this make sense? Or, if the settings are indeed the same, should the Roku pass the same signal to the TV as the internal apps, so the image should be identical? Very confused about this one. I'll be asking in the LGOLED sub as well in case those peeps have a different perspective.