The primary difference between these two is related to the need for lubricant. Carbide is a little bit more durable in the sense that they last longer than your standard steel reloading dies. Part of the reason that they have become so popular, beyond longevity, is the fact that a lubricant is not required. The steel options are still outstanding in terms of quality. Many manufacturers provide lifetime warranties on their steel die sets because of the quality in terms of design and development. However, lubricants are needed for use, adding cost.