When evaluating Teflon (PTFE) fabric, you must prioritize coating thickness and PTFE content, as these determine the fabric's non-stick properties and chemical resistance. Ensure the base material is high-quality fiberglass for dimensional stability. Key metrics include tensile strength (warp and weft), temperature resistance range (typically -70°C to +260°C), and dielectric strength if used for electrical insulation. For food-grade applications, the fabric must have a smooth, non-porous surface to prevent bacterial growth.