redfoxjumper Like @matchboxbananasynergy mentioned, I am using GOS on Pixel 9 Pro Fold. Can't really compare it vs stock as I haven't used it on stock but it works very well on GOS, I like the inner screen for reading articles, PDF docs or any other content that doesn't flow well on smaller screen. The hardware fingerprint sensor on the power button is very nice, I like it better than the onscreen sensor.
Not sure why but comparing to other Pixel phones including Pixel 9 Pro XL, the scrolling experience and touch gestures on the Fold feel much smoother when using the outer screen.