Whether one should consider later film adaptations or Gaston Leroux`s original novel, The Phantom of the Opera, more effective really depends not on the works themselves but on the audience and also on one`s understanding of effective. Effective is not an absolute but a transitive term – a work can be described only as having a certain effect on a certain audience. Absent an audience there can be no effect.
For audiences looking for strong emotional sensations, the film version probably evokes horror more strongly. The novel, especially because of the way the narrative is framed as historical, invokes a more reflective analytical response. Thus one could say that the movie is more effective for visually oriented audiences seeking intensely emotional viewing experiences and the book more effective for audiences seeking a balance between emotional sympathy and reflections about how the world treats the disfigured.