The esthetics and performance of carpet is similar to the fabric in your clothing. The type of fiber used, the construction of the cloth, and the color all play a role in the styling, cost, and performance of that garment.
Nylon
Nylon is a durable fiber that has good resiliency and good stain resistance. It is a strong fiber, which makes it suitable for the heavy traffic of a commercial area or active household. It is typically more expensive than olefin and polyester based carpet.
Polyester
Polyester fiber has some of the most beautiful textures and colors available, and is durable and resists wear. It is susceptible to crushing, but has excellent resistance to stains. Most polyester-based carpets have a luxurious feel (hand) that people love to dig their fingers into.
Polypropylene
Polypropylene, also known as Olefin, will not absorb water and must be solution dyed (pigmented) to give it color. Solution dyeing is a pigmentation process in which color is actually built into the fiber when it is formed, making it an inherent part that cannot be removed from the fiber. The color will not fade, even when exposed to intense sunlight, bleaches, atmospheric contaminants, or other harsh chemicals or elements. However, since it is not as resilient as other fibers, polypropylene is normally used in loop pile constructions in which there is less need for superior resiliency.
Wool
The preeminent natural fiber and used in the manufacture of carpets and rugs longer than any other fiber. In fact, the weaving of wool carpets has been traced back to 3,000 B.C., and wool rugs and carpets have been prized as objects of beauty and prestige ever since. Wool does not have the stain and abrasion resistance of some of the man-made fibers, but it has an enduring quality, and many wool carpets and rugs are said to "age gracefully." Soft underfoot, wool also offers the somewhat intangible consideration of prestige. However, wool carpets are considerably more expensive than most synthetic carpets and represent less than 1% of all broadloom carpets sold.