Different varieties of Herbal Essences, on the shelf in Sainsbury's... Apart from an almost indistinguishable change in the aroma, what actually is the difference?
Well, some make frizzy hair smooth, some make dark dyes look good for longer, some make dry hair more moist, some keep blondes bright, some are really good for curly hair and some are good for straight hair. That help at all? :-P
Should add - apart from seeing the evidence for coloured hair shampoo keep colours vibrant (personal experience), I don't know how well any of these work.