A lot of people are pretty skeptical about Sulphates and Parabens in their shampoos or other cosmetics.
Sulphates are not bad for your hair. Infact they are cleansing agents and it's fine to use a shampoo with sulphates. No they don't cause cancer, don't cause any illness as far as most medical researches have shown. Just condition your hair well with some oil or conditioner.
Parabens are sometimes bad, sometimes not much harmful. While it has been shown in a few researches that Parabens can be absorbed topically, there is still very rare evidence that it can damage your health. They are bad for your hair, so steer clear of such shampoos.
This WOW shampoo is a decent shampoo, nice smelling, consistent and we'll marketed, but the asking price is too much. I would probably go for some other shampoo from Himalaya Herbals or Khadi.