I've used this for about a year. It's good, but it's a highlighter, NOT a concealer. It gives light to the dark area and draws attention away from the flaws.
The only problem I have with it, and this started about a month ago, is if I use it every day, I get dry skin under my left eye. Not my right, just my left! I use a good moisturizer and undereye cream so I'm not sure why it's having this effect, but I still like the product.
It's expensive, but you only use a small amount and it's in the form of a pen so you can control how much you use. I've had the same pen for nine months, but it is time for a new one. Hope this helps.