My new (okay, there was a big tear on the back of the dust jacket, but I'm too lazy to return it to Amazon) copy came in a few days ago, along with Trinity: An Illustrated History of the World's First Atomic Test. As I expected, it's a big expansion of the original edition. I don't have a copy of the original anymore, but a quick browse seems to suggest that nothing from it was removed, and the new graphics have the same visual style as the originals. As much as I liked consistency of Specialty Press's 10x10 in format, I think the 8.5 x 12 in format does give it the pictures and text a bit more breathing room.
It's going to be raining nonstop the next three days, so I'll probably post some low-res preview shots soon.