Saucony has crushed it with the Women's Endorphin Speed. There's no doubt this shoe feels fast. In short, Saucony has combined a new ultralight/soft midsole foam with a composite plate that makes any run feel fast. In addition, Saucony has added a shape to the outsole they call Speedroll - it adds a lively feel from step to step.
This is certainly not a shoe only for the fast, any women who wants a very cushioned, light-weight neutral running shoe will feel these benefits.