I'd REALLY like to see one of those working a boat, with the boat bobbing up and down in the water. Even docked, the boat still moves.
It's another snake oil. Oh, it will probably pull in over-the-air stations, but, stick a paper clip in the coax cable connector on the back of your television and you'll get HD also. Maybe not as many stations, but you'll get them!
The flat antenna's that simply attach to the back of your television have been around for a while now. They all work about the same way. Without amplification and the ability to move them, you're wasting your money. The batwing on your camper is really the best you can get!