Clay tempering is a technique used in the traditional Japanese sword-making process to create a distinct hamon, which is the wavy line pattern seen along the edge of the blade. The clay is applied to the blade during the heat treatment process to create differential hardening, resulting in a harder edge and a softer, more resilient spine. This differential hardening enhances the blade's cutting ability, strength, and overall performance.

Whether clay tempering is "better" depends on the specific preferences and requirements of the user. Here are some points to consider:

1. Cutting Ability: The differential hardness achieved through clay tempering can enhance the blade's cutting ability. The harder edge retains sharpness and edge retention, while the softer spine provides flexibility, reducing the risk of breakage during impact.
2. Aesthetics: The hamon pattern created by clay tempering is highly valued for its aesthetic appeal. The unique wavy line adds to the beauty and visual appeal of the sword, making it a desirable feature for many collectors and enthusiasts.
3. Complexity and Craftsmanship: Clay tempering requires a skilled swordsmith to carefully apply and control the thickness of the clay coating. This level of craftsmanship adds to the complexity and value of the sword, making it a desirable characteristic for those who appreciate the artistry and tradition of sword making.

It's important to note that clay tempering is just one aspect of the overall sword-making process, and there are many other factors that contribute to the quality and performance of a sword, such as the quality of the steel, heat treatment, geometry, and the skill of the swordsmith.

Ultimately, whether a clay-tempered sword is considered better depends on the specific needs and preferences of the individual. Some may prioritize the performance characteristics and historical authenticity associated with clay tempering, while others may focus on other factors such as durability, ease of maintenance, or cost.