I used my la toja stick just this morning...it gives the skin a glass-like taught finish, similar to MWF. I'm assuming it's due to the minerals.
I don't get skin irritation like I do from alum.
I specifically use La Toja when I am using any new razor or blade for the first time. This way, if I give myself a nick or weeper, the salts in my lather is already working on it.