I knew a girl in college who had hers done. We had the same math lab together so we'd hang out for about an hour before. I was always jealous of how perfect her eyeliner looked even at the end of the day! I was about to get my first tattoo so I mentioned it to her, and she told me the only tattoo she had was her eyeliner
I was like "OHHHHH that explains it!"
Anyways, I think it looks really cool, but I would hate to have to keep getting it redone. I have thick black eyelashes as it is so it's not a big need for me right now, but I might consider it someday!