I've been using this concealer for a while, and it's been lasting a really long time! When I got it at first and rolled it all the way up, I was really disappointed in how little product there was, but I've had this "crayon" forever!
This does have pretty light coverage, but it's buildable. I like to use this for under my eyes and on any redness, so it's a great multitasking concealer! One thing that I really like about it is that I don't have to set it with a powder, which is great because I have other things I want to be spending my money on besides makeup. It doesn't crease under my eyes without powder, but it would probably last longer if I did use one.
I wouldn't use this on really bad under eye circles or a major breakout because like I said before, it has pretty light coverage. Buildable, but only to an extent.
I use this by rubbing it on my finger and then dabbing it on my face. I find that if I apply it strait from the crayon form it can be hard to blend under my eyes.