I'd have to say for me, it's defining my eyebrows. Up until recently, I didn't know how to do my eyebrows or even that you should fill them in. My makeup never looked complete though. Filling them in really does make a difference and it's true what they say-it frames your face.
The only problem I have is my eyebrows are pitch black and trying to find a color that looks natural is quick tough. Black is too harsh and dark brown is too obvious and un-natural. If anyone knows of any good brow colors for black eyebrows, please let me know