Correct way of getting asset/blueprint paths?

There are 2 ways (if not more) to get the path to load blueprint assets like meshes, materials, sounds, etc. But which one is the one we should be using and why? Example:

"SkeletalMesh'/Game/Assets/Characters/Rat/Mesh/Rat.Rat'"

versus

"/Game/Assets/Characters/Rat/Mesh/Rat"