Users are generally much more familiar with one type than the other.
This causes some confusion when the user's expectations are based on experience with one type and the reality of the pump's operation is based on the other type. Contrasted, herein, will be the differences in operation of the two types of pumps through real world examples where the characteristics of each were used to advantage. Centrifugal and positive displacement pumps operate on completely different principals. With centrifugal pumps, flow results from a pressure differential created by the pump. For a positive displacement pump, pressure differential results from flow created by the pump.