I purchased these Ryka shoes to wear at the gym.  I chose Ryka because I have a pair of slip on Ryka Desires that I am crazy about.  The Dynamic has the same great fit (narrower heel, nice toe box width, glove type fit around the sides and top of the foot- like a hug for my foot!), but Dynamic lacks the cushioning of the Desire.  If not for that, these would get 5 stars.  I also love the blue/purple color!  It gives me a boost for my workout.  I would definitely recommend these for cross training, but for a heavy running program, probably not your best choice.