i agree that the type of the exfoliator should be chosen according to the skin type and the result wanted to be achieved.
Throughout my experience as a beauty therapist i worked with various makes of skincare. Personally i prefer non-grainy exfoliators ( i find them irritating) I use Guinot Gommage Biologic, its very pleasant and very effective.
I also think if using grainy exfoliators they should not be sharp ( i prefer man made grains, example - REN Jojoba microbead scrub), Sharp grains scratch the surface of epidermis so badly that skin switches on the defence mechanism and produces skin cells quickly protecting the surface from further damage. The effect is - the person exfoliates constantly but not achieving any results but drier skin.
AHA based exfoliators may contain small grains that are made mechanicaly meaning that they are equal and not sharp, which allows to use those scrubs more often. Graines exfoliate the dead cells and aha exfoliates dead and dying cells.
hope this helps:hug: