I have been training in the Minimus roads for over a year without problems, but things are starting to get bad, I've got matching black toenails on both feet, I had pain in the ball of my left foot, and pain on the outside of my right foot, not to mention an annoying ingrown toenail on the right foot big toe. And this shoe sucks on rainy days! My legs feel beat up after running in these when they are wet. And I am a forefoot runner.
Requirments: Flexible, light, big toe box, and probably a low heel to toe drop