This eyeliner set comes with a mini brush, which actually isn't too bad. I really like the look of this eyeliner because there is depth to the black colour. I would get about 2 hours before the eyeliner smudges and this eyeliner flakes when wet. On the bright side, the line stays well-defined for more than 8 hours, despite smudging on the eyelids.
I don't think the eyeliner is available for independent purchase yet, but I would not purchase it anyways. I look forward to trying out the mascara from the same line.
Update (January 9, 2013): Seventeen Backlash Mascara
I really like the brush of this mascara, the bristles are close together but feel very soft on the lashes. The formula achieves a very natural look that lasts 4-5 hours before smudging. I don't think I like it enough to repurchase.
What is your favorite gel eyeliner?