I had been searching for a sulfate-free shampoo that was not as costly as many others and found what I liked in this L'Oreal product. I have used two so far, one with a light chamomile scent and the other with a more herbal rosemary scent. Only a small amount is needed to produce a light lather which cleans well without over-stripping the natural oils and expensive hair color. These types of shampoos cost a bit more than the more common versions which include sodium lauryl sulfate as a main ingredient (that which creates the "bubbles") but as indicated, less is needed, so one tube lasts and lasts. I have no quantitative analysis that my hair color has lasted longer as a result, but it does seem that I can stretch out more time before my next needed color session. Effectiveness Giving it an 8 only because I have never really calculated how much extra time I have between color sessions. Stretching that out was the reason I bought the product in the first place. Scent I like the two scents I have used - a chamomile and a rosemary. Would like to see other scents introduced.