One should not experiment with shampoo's in my opinion but rather your conditioners and treatments. Once you have found a shampoo that is gentle on your scalp, cleans very effectively and leaves your hair in the best possible condition, you should stick with it. I have been using Head and Shoulders as my shampoo of choice for the past 5 years and I never even had a problem with dandruff besides the occasional dry spot now and then that got a little itchy.
This shampoo makes my hair look healthier which I need as I have such fragile hair. It leaves my hair feeling shiny and soft. I mix up my conditioners and treatments along with using this shampoo permanently and so far I have been very pleased with the results. I will only use another shampoo if I think it is 100% worth doing so.