What is the difference between the Flat and Immersive viewers?
Immersive viewer corrects the optical distortion when the images are stitched together. This is especially useful when the photos are taken with a wide-angle lens. The immersive viewer also allows you to zoom in and out of the panorama. The Flat viewer generally gives a sharper image when compared to the Immersive viewer. Most of the time it comes down to personal taste … please look at the demos in samples to see the difference for yourself.