This is my �photographer� side writing you today. The challenge with many of the low to mid-price concealers is that they tend to be too heavy, resulting in a defined point where the concealer show up once the base sets.
I agree with Daffy regarding YSL Touche Eclat. It�s an excellent product. However, based on your age group, you may wish to consider one of the Guerlain products, particularly the 'Touche de Teint.' It tends to blend more naturally.
In addition to dark circles, if you�re encountering any puffiness, in France we would typically use chilled serving spoons and rub the base gently around the base of the eye and above the cheek bone. It�s even more appropriate during the seasonal changes when you tend to put on make-up in a warm home, then step outside into the cold. This can directly affect the natural earthen elements of many cosmetics, giving your face a definitive �made-up� look, rather than a natural look.
And one last consideration. As down-market as it may sound, some of the Boot�s Number 7 products are proving to be comparable if not superior to some of the most pricy (and gimmicky) products on the market.
If you�d like expert advice, rather than from a beautifully made up young lady who has attended only one or two courses on how to apply make-up and sell it at the same time, try contacting the Guerlain counter at Harrods and ask if you can book a session with one of their cosmetic consultants. They are typically in the stores 4-6 times a year.
If this is out of your area, I�d suggest trying one of the Elizabeth Arden Red Door locations, where you can obtain the same advice and equally good products. However, for concealers, I still endorse Guerlain above all.
I wish you well
Fr Bill