Hard to say without knowing the model of each. Reese made both proportional and time delay brake controllers. Time delay controllers are junk, they don't measure how HARD you're braking, they just start with a light trailer brake application then ramp it up depending on how LONG you hold the brake pedal down. The overall age and condition of the controller is also an important consideration. You don't want to cheap out on a brake controller that may fail and leave you without trailer brakes when you need them.