Gator Board is much stronger than regular foam board, but is about the same weight.
Gator Board has a very rigid poly surface which is resistant to moisture, unlike foam board which is foam covered with lightweight paper stock.
Gator Board has an extruded polystyrene foam encased between layers of a melamine and wood fiber veneer. Gatorfoam / Gator Board has a much harder outer surface than other foam core boards and resists warping.
Gator Board is not an acid free material, so you should check before using it for items which will be displayed in museums or other permanent archives.
The firm surface of Gator Board is it's advantage and is a very durable permanent board useful for building displays, and as a backing for more permanent signs, and as a backing for artwork.
For miniature builders, Gator Board is often used as a backing for wet materials like paper-clay or stucco finishes which require a water resistant backing while the coating dries.