Page Preview is completely broken on an iOS device where it won't go away and even when it works as expected it's distracting, covers up what I'm reading and depending on how link laden the page is I have to be very careful how I scroll to avoid distraction.
I appreciate there is a way to disable it but it requires disabling it on all devices. If you at least have away to set it to disabled via a URL parameter then that will make it easier to share across multiple devices and it's a non-issue if the cookie eventually gets expired or culled.