This package contains fantastic terrain in Unity format, prefilled with dozens of trees and veg planst, rocks. You can add few props and level is ready to go. Each tree is placed by hand to have perfect position.
Other model formats do not have terrain included but contain 15 trees, 4 grass blade textures, an electric pylon (2 lod stages), 10 ground textures and mushrooms. The Unity package contains additional content like a river prefab and 16 rocks embedded in a huge populated Unity terrain.