...and I do use it fairly often, shooting with my iPhone or my iPad Mini. (I also shoot with high-end "bridge" cameras and use Photoshop CS5.)
What would make it five stars for me? More exact edge-matching when doing the HDR blend in very high contrast situations, such as getting the interior of a room and the bright blue sky out the window. As it is now, there is a pretty wide area of gradation that makes the shot look very much HDR. (And no, Im not talking about camera shake!)
Otherwise, functions well in lower-contrast situations.