The new PDF viewer on mobile is fantastic, the only thing missing from my perspective is the ability to zoom in and then move the PDF around. You can kind of do this with 2 fingers, but it is finicky. Ideally you could zoom with 2 fingers and then use 1 finger to move around.
Additionally when zooming in, it would be great if the height adjusted to allow more of the screen to be used. For example, I have a button, when I click it that takes me to a PDF page where the only component is the PDF viewer, when I pinch to zoom it works, but I am only using maybe 1/3 of my screen real estate.
I'm glad to hear that you're getting good mileage out of the new component and will make sure the mobile team hears this feedback! As soon as there's news to share, I'll provide an update here.