Carboload is more readily available for your plants roots whereas molasses ins't readily available, your plants root system has to break down the molasses before it can accept it. There is more sugars in carboload than molasses. Look on the back of carboload, you'll see a bunch of "ose's" like (glucose) or (sugars).
Plain and simple it has more sugars than molasses and is more readily available.
Keep in mind your going to have to pay more for Carboload than molasses. !!