My wife and I both used Z Flip 4 for over a year. Mine isn't my daily anymore but it's still fine. Wife's inner screen died on hers just after the warranty expired. I guess that's mixed results. 😄
Honestly I've thought about going back to mine once or twice since my Pixel 8 Pro had some issues (now mostly resolved).
After my wife's started dying I was concerned mine would as well. If hers hadn't crapped out I'd probably still be using mine.
Edit: There's always the possibility that mine would have stopped working at some point, too, had I kept using it. After switching I mainly use it when I sleep now, so there's been much less daily wear and tear. Who knows?
I was afraid if I waited until the screen died it would make it harder to transfer to a new phone. I do cloud backups but I don't know how hard they are to restore when going between phone brands. USB transfer seemed safest bet.
As for watching videos, I do like that you have the option to fold it like an L so you don't need a stand or anything if you don't have something to prop it on and you need your hands. They also have a "camcorder mode" where they work sort of like a viewfinder when recording video which I found useful. The difference is mainly how you fold and hold it.
Sound was pretty good but not great on mine, but that's most phones I've had experience with if you're not using buds/cans.
Edit: My good Tech Spurt dude did a thing recently comparing moto and sammy that you might find helpful. He may have other full reviews of the individual phones by now, too. https://youtube.com/watch?v=XFtMrPPcL00
I think they're figuring it out. The hinges must have been a real engineering challenge, not to mention the flexibility and durability of the screens. Remains to be seen if they're around long term.
Yup fold it like an L for camcorder mode or when you need a stand. Some apps switch modes when you do that. Like with YouTube it'll put persistent controls in the lower half while it shows just the video in the upper half. Probably also good for zoom or teams or other video calls since it becomes its own stand for the camera.