I have incredibly oily hair, and have to shower daily. AND my hair gets very accustomed to dry shampoo, so that after a few months of using it to try to get by with showering every other day, my hair just laughs and says, "Naw, I'll just look oily and stringy anyhow, fool!"
I've been using cheap brands like Suave and Dove, and have recently been using NYM with success. But this is in another league. It has a great power of spray, and it leaves my hair voluminous and free of that oily look. It does leave a white residue easily (I have pinky purple hair), but as long as I spray in short distant bursts, it is fine.