I've always loved liquid liner and gel-liner, but its taken me a long time to buy into the 'felt-tip' liner scene.
Within the space of about a month, I know own two. One black, one blue, both by Eyeko. If you're looking for fast, accurate eye-liner application, I would definitely recommend these. They are incredibly long lasting, and once you get the knack of them, very easy to apply. One thing I would say though, if you are right handed like me - for some reaso, I find the application on the right eye a lot harder! Something to do with the angle of the pen, but I can work round it.
And if you're looking for something with a bit of pop, especially for spring/summer, I would definitely recommend the blue, paired with natural eyeshadow and pink lip gloss. Its not overtly blue, and is a great alternative to black.
E x