We've just bought our first set of the Popup Gizmos for our new Roo. Haven't taken them out of the box yet, but will be taking them with us on our first real camping trip.
We've been told by folks who've used the Gizmos that they are worth the money because the Gizmos make the bunk ends cooler when your site is in direct sun. And apparently the Gizmos cut way down on condensation on the inside of the canvas. It's quite unpleasant to wake up from a sound sleep when cold water drops onto your face from the condensation.