The Schwing Liquid Eyeliner by theBalm Cosmetics is highly recommended by gretta in their video review. They praise the brand, theBalm, and describe it as a really nice brand. Although gretta does not open the eyeliner in the video, they emphasize that it is a black liquid eyeliner and express their love for the brand. Overall, gretta highly recommends the brand and suggests it for anyone in search of a good eyeliner. However, no specific benefits or drawbacks are mentioned in the video review.