And it's not just the "nicer bounce after a scroll", its the whole UI interaction. The thing that iPhone fans like about their products is how the interface disappears and you don't need to think about it. The touch interaction model makes the user think that they are directly interacting with the content itself, rather than through the intermediate of a controller, and that this content is actually physical, rather than a representation on the screen. It's an illusion, but it is a compelling one. Examples: * The right bounce after a scroll, and the right inertia when you flick to scroll through a list; * Dragging your finger to pan around a map or large web page; * Icons and buttons changing their appearance instantly to show that they've been pressed.
It's little things that give immediate feedback to the user that create this illusion, and it doesn't take much to break it and remind you that you're using a device. What MG and Gruber keep pointing out is that Android keeps breaking this illusion, for example with stuttery scrolling or laggy/inappropriate feedback when you push buttons.