Hard anodizing leaves a surface hard enough that you aren't supposed to be able to scratch it with a screwdriver. Regular anodizing has to be sealed or it will come off on your hands. It is not very durable. The drawbacks to the anodizing process are that there can't be any steel or other metal on the product to be done except the aluminum. Also, the person anodizing, has to know within certain limits exactly what kind of aluminum he is working with in order to control the process properly. Aluminum comes in a large variety of types just as steel does.