Storyteller is used with an iPhone for videos or time lapse either on it's own or in conjunction with ROV. Content created through Storyteller can be edited, saved, and shared directly through the app.
ROV Motion is for use with DSLR cameras and allows your phone to act as a controller for use with the ROV slider and to trigger your camera for time lapse. Content does not save to this app. Editing will need to be done via a third party editor.