When evaluating COB (Chip on Board) LED modules, you must prioritize Luminous Efficacy (lm/W), which should ideally exceed 120-150 lm/W for high-end applications. Pay close attention to the Color Rendering Index (CRI); for indoor or commercial lighting, a CRI >90 is essential for color accuracy. Additionally, verify the Thermal Resistance of the ceramic or aluminum substrate, as efficient heat dissipation is the primary factor determining the Luminous Decay and the overall lifespan (typically 50,000+ hours) of the module.