I have really wrinkly, heavy-lidded eyes (always have; you should see my baby pictures!) And I always admired the look of liquid liner but never could figure out a way to make it work for me. It was too hard to apply without messing up and it would ooze into my wrinkles. It didn't help that I have a hand tremor, so there's a lot of trial and error involved in applying makeup.
Stila's liquid liner has changed all that, though! I love it. The felt tip makes it easy to apply, and if I mess up I can just wipe it away with a q-tip- but it stays put until I WANT it to wipe off! It leaves a clean line with pure color- no blotchiness, and it doesn't smudge or fade.
I can't praise it enough. I want one in every color. :)