I started using gel liner recently (the NARS Eye Paint in Black Valley) for a change of pace. I usually use liquid liner in pen forms (Kat Von D Trooper liner pictured) which I have really enjoyed.
As far as the liners pictured go, both are stellar. They last all day and are mega black. The one thing I will say that is different is the ease of application (at least for me) and its not that gel is messy or liquid is annoying. Its that for gel liner you need to get out your brush (I love using a super skinny brush for the most control) and do the whole dip and swirl and jazz. Its just more of a hassle for me on-the-daily. I really do love gel liner, and I especially love the matte finish of this gel liner. But man, that whole deal with the brush is just more hassle that I am willing to go for at 7AM.
I find myself reaching for my gel liner more during the weekend when I have more time in the morning or when I really want that gorgeous matte black finish. I dunno, I might be spoiled by pen liners, but liquid liner in that form is just so much faster.
What about you? Are you on team gel or team liquid? Why do you prefer one over the other?