I used to be a big product snob until my dermatologist talked me into trying some other products. After a couple weeks my skin was much better than it had been on the super expensive products. After the samples she gave me (spectrogel and cetephil for cleanings and moisturizing, neutrogena for SPF) ran out I switched myself over to cheap natural alternatives (I'm a tree hugger and want to use natural products not tested on animals). I now use Korres face wash and Weleda. I have 30+ skin that's still oily with the occasional outbreak. The derm told me NOT to use acne products, only use gentle products regardless of the skin type. I do use Retin-A micro; a prescription that helps both pimples and aging. It has made the biggest difference in my skin's appearance.
There is a lot of truth to what experts say about the same ingredients being in the drugstore brands as there is in the highend department store brands. Some are identical with the exception to packaging and fragrance!