I love the shampoo but since my hair is colored, I am not using it.
You can tell though that the shampoo is a high quality shampoo because it takes very little to clean your hair. I have shoulder length hair and hadn't washed it in a few days before using the shampoo and it only took a little over a pea size amount the first time I lathered up (I lather up twice). The second time I lathered up, I was concerned because there had not been much lather the first time - but my hair and scalp were squeaky clean - I mean - I could hear it squeak as I tried to work with it.
I was told once by a hair stylist I believe that the higher quality shampoos won't lather up as much as the cheap ones you get from Walmart and the drug store and stuff - but you also only need to use a tiny bit of them - so they wind up being almost as cost effective because a bottle will last you so much longer and be good for your hair.