I recently bought Swastik shikakai soap, as an alternative to shikakai herbal powder.
Pros : good for quick hair washing, leaves no messy residue in the shower like the herbal shikakai powder does. Scent is not objectionable.
Cons : the pH of the soap may not be balanced for hair use, because it did dry out my hair quite a bit. Leaves a film on the hair. Does it have SLS or other harmful chemicals? Dunno, as the soap sleeve has NO listing of ingredients....typical marketing slyness of certain Indian products.
I did find another shikakai soap - Jasvant shikakai soap, which claims to be pH balanced and all natural. Haven't been able to order it yet.
Summary - best to use this soap as a quick alternative to herbal shikakai, but not make it a habit to use the soap for the hair. Nothing beats the herbal powder!