Quality mode for stability, but since I have the Pro, performance mode is stable enough now.

Performance always. Most games I have a very hard time seeing the visual difference between the two modes. So i just opt for smoother framerate every time.

Typically performance, but it depends on the game.
It's great that consoles now give players these options, but I'm hoping they get expanded upon on in the future. I do prefer being able to freely tinker with the settings (as I can do on PC) to create a custom experience, as opposed to using some kind of premade preset.

Performance 100%

Visuals can look pretty but means nothing if its slow 30 FPS or worse.

Yup, maybe it's cause we are fairly hardcore or hardcore adjacent gamers on here but if this is the split then Sony and MS need to push devs to focus on 60 fps or balanced modes. If Cernys 70% is true and this will likely increase as the generation goes on then idk why the devs still chase fidelity, it's frankly a waste of money and resources when the minority make use of and graphical goals can be set lower, decreasing the length of game dev and everyone wins. Smaller budgets so more profit. Gamers get a smooth 60 and the industry doesn't implode.

Whoops meant to say I prefer performance usually of it's between quality and performance. Though give me quality if performance is very unstable. Big framedrops hinder me more than constant 30 FPS. After all I survived PS4 and that system has many great games that I played in 30 FPS.

Modes like SB balanced and RC Rift Apart Performance RT hit a good sweet spot for me though. Since the few drops that are there are very minor and you get a lot eye candy in return.

It depends a lot on the slider, some are very relevant others are barely noticeable in my experience. I do like good AA and a big draw distance though. Because I dislike pop-in. As I play 1440p I usually safe a bit on texture quality and reflections.