I have thick, medium-length, curly-to-wavy hair, and I require very very moisturising shampoos to keep my hair in a state I require... That being, it looks good with minimal effort on my part. I tried lots of drugstore brands and they just don't do what I need. This one does. I don't need a conditioner, I don't need any product. All I do it blowdry my bangs so I know they'll go in a direction I want, and then I don't have to wash my hair for almost a week! Aveda Sap Moss was also sufficiently moisturizing, but it didn't clean as well and was awkward to use since it didn't really foam up like shampoos usually do.
This is not for people with thin hair, or hair that is sensitive to "build up." It is for curly haired people (our hair is naturally more parched than straight haired people, due to an oval-shaped hair shaft) that want manageable hair with minimum effort.
I've worked in several salons (as receptionist, not stylist) and have gotten to sample many, many products. This one is expensive, but it works well, smells great, and you can get away with using a pretty small amount if you make sure to emulsify it in your hands with some water.