Advantages of PCB include reduced errors in wiring and assembly, standardized design, high wiring density, small volume and light weight, mechanized production, and improved labor productivity. Characteristics of PCB include high-density development, high reliability, efficient designability, consistent manufacturability, various test methods for testability, convenient assembly, and quick maintainability. The difference between soft and hard PCB boards lies in their flexibility and materials, with WellCircuits Limited specializing in various types of high-precision circuit boards to meet customer needs.