It is water-resistant. This means it will repel water and survive showers very well, but we don't recommend taking it as your dry-bag during a tropical downpour.
Firstly, it is significantly larger. 35L compared with 28L. It also has a lot more organization internally - 2 large storage areas as well an an organization pocket on the front. The packing videos of each bag will give you the best idea of the differences in function and capacity between the bags.