Synthetic carpet can be nylon (the most popular), polyester, or polypropylene, which is sometimes referred to as olefin. These are the most common synthetic fibers used for carpets, and each has its pros and cons. Synthetic fiber carpets — especially nylon — sell better than wool, but that’s often because of the higher up-front cost for wool. Still, there’s more to carpet fiber than just price. It’s important to look at the strengths and weaknesses of each and consider things like where it will be installed and whether it fits your lifestyle well.