Fallen,
Contractually, Chaney's face as the Phantom was prohibited to be shown in publicity materials, so this is why, too, one can come across lobby cards that actually have Chaney's face masked out. A good idea, in order to keep the mystery and anticipation of his appearance heightened until moviegoers actually saw the film.
The particular OS, showing Chaney underwater, as he approaches the boat, with his hollowed breathing reed, therefore, in many ways, stands above the others, because it depicts Chaney, albeit in profile, and somewhat obscured, as he did look in the movie. Mary Philbin looks beautiful on this particular OS, as well. It is easy to understand why this style OS sold for $155,350 in HA's November 2008 auction. (This is the only style of the OS they have offered, as well).
The other artist's interpretations are wonderful, too, of course. Creative, artistic, and beautifully executed stone designs in their own right, as well.