I have a pair of Skechers tone-up trainers. There're a little like MBT shoes re. the heel to toe roll motion, but less rigid. Most of the info I have read about so called 'tone-up' shoes point to weight-loss claims as a marketing gimmick!
All I know is that since I bought my skecher's tone-ups, my posture has improved, I find walking much easier and my feet, hips & knees don't suffer as much. The comfort factor alone I would rate them very highly - I'm pleased I bought them.
Check-out Amazon prior to making a purchase as there's some useful customer feedback.