When it comes to the bungees stretch and power, these two bungees are comparable. In the industry the main difference between these two fibers are the abrasion and UV resistance. Polyester is naturally more UV resistant and has a higher resistance to abrasion than standard Polypropylene. We use a high tenacity UV treated Polypropylene, which improves the resistance of the Polypropylene to both of these in comparison to much of the other Polypropylene bungee available elsewhere.