I tried the skinny pencil first and I LOVE it!! It is black enough and you can build the color. The point on the felt tip allows you to draw your line as thin or thick as you would like. I was so in love with the skinny pen that I went back and bought the fat pen. I like the fat one for extreme winged liner. I have a hard time drawing a thin line with this pen, but I love using it to wing my liner out!
They are about $8-$9 and can be found at Walgreens or any local store carrying Milani Cosmetics. I think these would be especially easy to use if you have a problem drawing a winged liner or just starting out with eyeliners!
If you decide to try these out, let me know how you like them! Or if you have an eyeliner that you live by, tell me about it so I can try it out!