Hmmm, I've not heard anything re: bite killing. It's definitely had points where it affected my ability to chew due to things shifting, but that's been easily countered each time by my Ortho just shaving down or adjusting the appliance - it's been due to my bite putting more pressure on the left or right row as I adjust. Other than that, over ~6 months so far I haven't really had much to note. I just wear it while sleeping and periodically while coding (since I'm not needing to talk during that... it's like "free time" for it to work) and it "just works".

Quality of sleep is through the roof, I'd forgotten what good sleep is like. If I miss a night of sleep with it (e.g, I travel and forgot to bring it with me) I absolutely feel it the next day.

Tinnitus-wise, I noticed that it got worse at first but then settled and is actually more in the background than it used to be. FWIW, I've had tinnitus for as long as I can remember, so I'd consider myself ~90% habituated to it - it doesn't bother me outside of any concern of it getting worse. I think this has made it easier for me to objectively judge whether something is helping or not - if my tinnitus is never cured, but never gets worse, I'll be fine.

https://vivos.com is what my Ortho got me on. I can't speak to others, but this has worked well for me so far.