As the demand for modernization grows across z/OS environments, system developers face a critical choice between continuing with traditional HLASM and embracing newer tools like Metal C. This session presents a practical comparison between development in Metal C and HLASM, showcasing how Metal C enables faster development, better maintainability, and comparable — often superior — performance. Attendees will see real-world code samples and benchmarks illustrating how Metal C simplifies system-level programming without compromising control or efficiency. We'll also cover how Metal C reduces the skill barrier: new developers can be onboarded faster, with less reliance on highly specialized assembler knowledge. This session is ideal for z/OS architects, application developers, and systems programmers who are considering transitioning from assembler to more modern, C-based approaches in their low-level codebases.