Had an older one of these a while back that worked great.  It always dispensed the right amount of food and never had a problem with it.  This one, I have set to dispense 1/4 cup twice per day.  It dispenses 1/2 cup twice per day and spills out food randomly at other times.  I'm just using standard Blue Wilderness cat food.  So now my cat is fat and I've gotta put her on a diet