I used to use Innoxa liquid liners - I bought it in black and purple
it was actually like a pen to hold so very easy
i recently bought the covergirl line exact liquid liner which is more compact and i find that has even greater control. i prefer the ones where you don't have to dip the applicator in the liner ink --these ones have the ink come through the tip and glide on
i tend to use a pencil on lower lash line so i can smudge it a bit and the liquid on top lash line over the eyeshadow for a really defined look
but now i am intrigued by gel liners...