These two are almost identical!
NARS Velvet Matte Lip Pencil in Bolero (pink cantaloupe)
According to NARS' website, this jumbo lip pencil contains a combination of unique silicones for a long-lasting wear. It's also enriched with vitamin E. These two main ingredients probably contribute to the creamy smooth texture of the pencil. It glides on very easily on bare lips however, it is so drying that it settles into fine lines and makes my lips look cakey. My solution is to apply this lip pencil over a lip balm (blot dry with a tissue first to rid of the oil) or a lip primer then gently press the color onto the lips with a fingertip.
Topshop Lip Crayon in Coy (coral blush)
The Topshop version is a little chubbier in size and even more drying in texture. It is also thicker and more opaque in consistency. This pencil settles into the fine lines just as much but with a gently press with a fingertip on the lips after application will fix the problem.
The color difference between the two is almost invisible to naked eyes. The Topshop may be just a tad bit brighter but I don't think you can tell the two apart once on the lips.
At $11 cheaper, Topshop may be a better choice considering the end result is almost identical.
But to be honest, I typically don't use them as a lipstick. I much prefer them as a “lip concealer” to cancel out my natural lip color (I have pigmented lips). This works great when you are going to apply a light-colored lipstick that otherwise may never show up.
I hope my review was helpful and that it gave you some ideas on how the two compare. Let me know if you have questions in the comment section below. :)