It all depends on the thickness of the steel. This particular point deserves special attention. If the thickness is expressed in thousandths of an inch, higher is better. If expressed in gauge, the lower the number, the thicker the steel. Ask for the thickness of the steel on both sides, exterior as well as interior.
Another important consideration is the type of impact. It is obvious that if a car hits a garage door at 6 mph, it will heavily damage the door, whether it is covered in steel or aluminum.