The Bobbi Brown webite describes this product as "a yellow-based Creamy Concealer that instantly camouflages dark circles. The creamy formula goes on smoothly with skin conditioning ingredients to help minimise the look of fine dry lines. This kit includes Creamy Concealer on top and Sheer Finish Loose Powder on bottom to set concealer for long-lasting wear".
I really like the idea of combining the setting powder with the concealer however, as many people have commented before, the powder compartment does get very messy after a while as there's no way of controlling how much product comes out. So the design of that could be improved on. The powder is super finely milled and creates a really natural finish but as I said, the packaging makes it awkward to dispense the product without ending up getting it everywhere. 
As for the concealer, I was very impressed by the consistency and long lasting effect it gave. It brightened up my whole eye area and the consistency is, as the name suggests, creamy but it's not one of those concealers that take forever to sink into the skin. It blends in really well and doesn't sit on top of the delicate skin surrounding the eye, it doesn't have that 'tacky' feel that some concealers have. The most important thing about undereye concealers has to be that they don't sit in the fine lines or look heavy/cakey. This product really delivers on that score as it feels light to wear, a little goes a LONG way. As long as you don't overdo with the application, you will be left with a natural looking, brightened eye area. Because I have under eye dark circles that are hereditory (which means they never completely go away), a product like this is fantastic for dealing with that problem. It doesn't dry the skin or irritate my eyes. 
Although the concealer is yellow based and a pink based concealer would normally camouflage dark circles more effectively, this product works really well. If you have more problematic dark circles, then you can always apply a salmon pink colour corrector before applying a concealer over the top. Keep in mind though, that you should always apply product sparingly under the eye as you don't want to heap a load of product on there or it will just highlight the area rather than disguise it.
The other great thing about this concealer is that there's a wide range of shades available so you can get an exact match to your skintone. The shades can be viewed here http://www.bobbibrown.co.uk/templates/products/sp.tmpl?CATEGORY_ID=CAT6087&PRODUCT_ID=PROD72642. The website also offers a Face Shade Guide so you can match what concealer you should be wearing in relation to your foundation shade. These kind of additions to cosmetic websites are so much more helpful than just providing a 'light', 'medium' and 'dark' concealer shade.
