Is BCF Polyester as durable as nylon carpet?

It depends on what you want to call durable. Regardless of what the product line claims, polyester, including BCF polyester, heat sets at a much lower temperature then nylon. This makes it much easier to crush under heavy foot traffic. This is not to say that you should never buy a polyester carpet. If this is a room rarely used, like a formal living room, it may be a good choice. Another time would be a child's bedroom that the carpet will be replaced in 5 years most likely. Polyester carpets are also very stain resistant. With current technology though, nylon is as well. The current push of polyester carpets is from 2 factors...both nylon and polyesters are polymers, they are made from petroleum. Polyester fibers can be made from recycled plastics. With oil pricing inconsistent and rising often, it is less expensive to make polyester. Generally the price is more stable. Second is really part of the first reason. As the economy as slipped and oil has risen, nylon carpeting has become more expensive. Retailers are able to offer the customer more in a moderate price range in polyester. Still if you look you will find high quality nylon carpets for a reasonable price. Carpet sellers want you to be uninformed buyers. Go into a store and ask to see only what you are looking for. Commission sales people push what they make the best commission on. If you state that you would like a nylon carpet, in a frieze style, with a good twist, but under $25 a yard...you might be surprised how many they have. If you are pushed to buy carpeting beyond what you have asked for, leave and go to the next store. Carpet pricing varies greatly from retailer to retailer.