This concealer is meh. It looks good when first applied, but tends to break down on my skin after a few hours, leaving it looking cakey and weird looking. And I don't even apply that much of it, at least not enough to warrant cakey-ness. I don't really like it, but I keep using it because I haven't found anything else that I really like. For reference I have combination skin that leans slightly oily.
I love this product, the coverage is amazing while being exceptionally light in consistency. It feels like I'm not wearing anything on my skin at all. It has a demi matte finish, which works well with my combination/slightly oily skin. The only con is that it doesn't last very long, even with a primer. I'm talking about only lasting 4-5 hours. Otherwise it's perfect. For reference I wear NC15 in Mac products, and am a shade 1 in this, which matches perfectly.
I have pretty good skin with some light acne scarring and redness around my nose. I also have combination skin, which borders on combination oily, sometimes a little dehydrated in the winter. This foundation was alright, it covered redness and did an okay job of covering my light scarring. It's so fine that you really can't tell that you're wearing anything. It gives off a mildly dewy finish, and smells like oranges. I wanted something that provided light coverage so that my freckles would show through, which is why I bought this originally. I was using Urban Decay's Naked foundation before this, which I really do like, but I went through a bottle fairly quickly and it's a little pricey. With that being said, this foundation gave me terrible cystic acne within 2 days of wearing it. I'm talking about really painful, deep acne that takes forever to go away. And I don't usually break out. So unless you basically never get acne no matter what, I'd avoid this product. Otherwise it's alright.. For reference I'm a NC15 and wore a C1, which was just a slight touch too dark for me. It'd probably suit someone with NC20 skin better, but since it's so sheer, it doesn't really matter.