Synthetic hair has come a long way in recent years. In some cases it is difficult to tell the difference -- The texture feels almost like human hair. Some of the higher quality synthetic pieces, you would never know they were not natural human hair if you didn’t have the human hair right next to it to compare!
Synthetic hair can often be worn right out of the box with little or no styling. The fiber used has "memory" for wave, curl and volume which lets hair bounce back into place with minimal effort -- the curl pattern is permanently set. It can even hold up in bad weather and can guarantee no drooping or frizzing.
Synthetic hair cannot be styled like its human hair counterparts. Only special Heat Friendly synthetic hair is possible to change the curl pattern. Keep in mind, even the heat friendly fiber can be difficult to style as synthetic fiber is more resistant to change. Synthetic hair is also less durable than human hair.