My son Jacob loves watching videos on the Playbook, and he is actually capable of navigating back to the video screen when he does not like a video or wants to change it. The way he is able to use gestures on the playbook confirms how intuitive they are. For instance, going back to home screen on the playbook is a gesture that almost means pushing something away since you did not want it.
Works for my son anyways...
And as for the HD camera, it does excellent footages. All videos on my youtube channel have been taken using the Playbook. I really enjoy it. They can be found here if you are interested in taking a look: jfguay2's Channel - YouTube