Leatherman for the following reasons:
1) Main blades are on the outside.
2) The file is diamond coated on one side. As you are in South America, I take it that a parang or machete is part of your equipment? The file is ideal for sharpening.
3) The saw, which locks, will cut bamboo etc.

Try running your SAK under a cold water tap. That should ease the blades.