I love, love, love them. I don't know how well they work as far as actually toning leg muscles as I don't use them for that, but they are incredibly comfortable. They are the only shoes I will tour WDW with! I have bad knees from years of ballet and when I'm wearing them I don't have to wear my knee braces. It's incredible!
I only have one pair right now but am planning on ordering one or two more for this summer. They're a little pricey but soooo worth it.