If memory serves, the screen is 150 feet wide and deeply curved. This is the first Disney 3D film that will match the all encompassing depth of Terminator 2 3D over at Universal, which has three screens, two of which are on the sides. Astoundingly, the 3D effect from the side screens is just as good if not better than the front screen. They've obviously had to solve some distortion problems at Philharmagic, but it should be an immersive, compelling experience.
AND, according to WDWmagic, they are already randomly picking guests out to view the film!