I've only tried one product from the Darphin range, but I'm very interested in trying more.
I use the Intral Toner, which is for sensitive skin. Mine's not particularly sensitive, but I like to use more gentle products. It was quite expensive, but lasted a very long time. I know I've raved about it in other threads, but really, I did notice a difference when it wasn't in my routine. My skin felt clean and fresh, it had a lovely smell, and very calming too.
I'd be interested to hear other people's experiences! But I read many times that Ashley Olsen is a big fan, and since I've heard it many times, I'm more inclinced to believe that she does use them, rather than journalists attaching her name to a product...