The difference is basically in the styling (emphasis basically). WCS is a more sexy, upright in posture dance, but it did evolve from lindy so there are many elements that are the same. I am mainly into lindy, and recently went to a WCS night. I did notice that sometimes the first triple step of the lindy basic/WCS whip was lost--probably to go with the difference in music. In general, it was the style that was different: WCS seems to be more latin-influenced and is NOT generally danced to SWING music.

Trees are people too!
¡Viva los árboles!