I can't believe I haven't reviewed these yet. I mean, I use them everyday (seriously), and I freak out when I can't find them. I'm seriously emotionally attached to these liners. I'll explain below.
First off, the price. These are pretty big pencils for $16. $16 may seem like a lot for eyeliner, but I use my Rockstar pencil everyday, and I've gotten about a third of the way through that pencil in the last four months. So they'll last you about a year. It's a good deal. The pencils themselves are really, really soft (like be careful when you sharpen them soft), which annoys some people but really works for me. Hard pencils are dangerous in the hands of clumsy people, but soft pencils are nice and gentle, and really easy to smudge into the lash line.
Now, the pencils themselves don't last all that long without primer. I can get from morning till about 3 without primer, but not any later than that. With primer, however, these pencils become completely waterproof and will last you all day. Just use the primer you use for shadow and get it a little closer to your lashes than usual. If you don't own primer, you should (it will change your life, try the Urban Decay one).
The colors are extremely pigmented, and the pigment doesn't fade at all throughout the day. If you want a colorful liner, I recommend Lust and Lucky. Lust is a gorgeous, very flattering bright purple, and Lucky is a beautiful bronze. For a more subtle look, try Rockstar. It's a dark, brownish purple that's softer than black, but defines the eyes really well, and works perfectly with the smudgy, smoky eye look. I'm seriously craving Underground, a metallicy dark taupe, as a summer alternative to Rockstar (I'll review it when I get around to purchasing, I promise). But seriously, give this liner a try. I've tried more pencil liners than I can count, and this is the only one I've repurchased. I own four of these. I don't own four of anything. That should say something.
Urban Decay 24-7 Liner, $16 at sephora.com
I pulled all the swatches I could find for you guys because it's just impossible to tell what color they all are from the Sephora website, and I don't know about you, but I def need to see all the colors before I buy (or just for fun).
3 liners: sephora.com
New swatches: makeupalley.com
First row of swatches: xsparkage.com
Second row of swatches: xsparkage.com