Melissa, a reviewer, highly recommends the Khol Eyeliner in Black sapphire color by Jillian Dempsey. In her video review, she mentions that the eyeliner blends in well and delivers impressive results. She describes the final outcome as something she loves and considers it her top choice for an eyeliner. Melissa's positive experience with the product indicates that it performs exceptionally well. However, since no drawbacks are mentioned, it can be assumed that the eyeliner does not have any significant issues. Overall, the Khol Eyeliner in Black sapphire color by Jillian Dempsey seems to be a reliable and highly recommended choice for achieving stunning eye makeup looks.