We know both alien races are real bastards, because before attacking the families, they go after animals (a raccoon in Signs and the family dog in A Quiet Place). Both movies also have parts where the son is out in the corn fields all by himself, like some sort of idiot scarecrow for aliens, with a flashlight as his only protection.
Eventually, an alien gets inside the house, forcing a character to hide in the basement. With no other options, the family has to fight back by exploiting the fearsome alien's rather silly weakness (high-pitch frequencies and water) and then killing it. Our theory: A Quiet Place is a Signs sequel, and in the next installment, we'll find out the aliens are also weak against dirt, spicy food, and light breezes.