I have pain in the ball of my feet, back and knees if I don't wear flip flops or shoes with proper arch support. I've spent over $400 on orthotics for flip flops but that didn't work for me. Then I discovered Olu Kai flip flops, tried the Ohana, Amo and Kulapa Kai. Of these 3 the Kulapa Kai is the best for me. The straps on the Ohana are thick and tight although my feet aren't fat. The Amo sizing is bigger and don't fit properly, the top sole is made of suede or leather and not as soft and comfy as the Kulapa Kai. After wearing the Amo for 1 night my feet started to hurt. I'm back wearing my Kulapa Kai and now my feet are happy. I ordered 2 more pairs.