Buyers should prioritize Luminous Efficacy (lm/W) and Battery Capacity (mAh). Ensure the lamp uses Lithium Iron Phosphate (LiFePO4) batteries, which offer over 2,000 charge cycles, significantly outperforming standard Li-ion batteries. The Solar Panel Conversion Efficiency should be at least 19-22% (Monocrystalline Silicon) to ensure rapid charging even in low-light conditions. Additionally, verify the IP Rating (Ingress Protection); for outdoor or emergency use, a minimum of IP65 is required to ensure dust-tightness and protection against water jets.