Trying to get my friend a new board

My friend is 5'1" and she weights about 115lbs. Her favorite board is the premier and has never rode a nice women's board. What are the positives to riding a women's vs a men's? Does anyone have suggestions on a good board and bindings for her? She has been riding for about 3 years and can clear the wake but she stands hunched over. I thought that may be partly due to the boards that she rides. Thank you!