In terms of their effect, a shaped charge is a drill, an EFP is a hammer. As a rule of thumb, a basic shaped charge will go through a thickness of armor equal to six times the diameter of the charge that creates it, whereas an EFP will only go through about one diameter. The EFP creates a bigger hole and does more damage on the other side, making it more effective against softer targets, but it has only a fraction of the piercing power.
