I have been using MAC's FLUIDLINE gel eyeliner for about 7 months, and I really like it. I use blacktrack (black), but it comes in about 6 other colors. The best way to apply it is with an angled brush, and it makes a very defined, clean line. It is very easy to make the line as thin or thick as you like. I constantly get asked what kind of eyeliner I am wearing. You can purchase this product at most department stores or any other stores that carry MAC products.