Neither Chromalox nor silicone is a heating element, so one can not be better than the other. Silicone is a generic name for a field of chemistry created by Dow Corning using the Si-O-Si compound to create polymeric chains. Chromalox is a multi-national corporation that produces industry heating products.
Chromalox manufactures a wide array of heating elements for many industries, some of which use silicone compounds in their construction. The actual heating elements are a wire mesh, or a foil, sandwiched between layers of a laminated silicone substrate. Silicone laminates are most often used in the company's medical heating elements, such as blood warmers, fluid warmers, hypothermia units, syringe heaters and sterilization holding trays requiring low to medium temperatures.