In my never ending search for a way to exercise without exercising, I recently bought some MBT shoes. The logic behind the concept seems sound but I wasn't sure it would translate in the real world. After wearing them everyday for about a month, I can say that some of the claims are true. First off, you definitely feel your calves getting a workout even after 5-10 minutes of normal walking. Supposedly the shoes are also supposed to exercise your thighs, back, and abs but I don't quite feel it in those areas. Then again, I'm just casually walking over relatively short distances and only for about 10-20 minutes at a time. Perhaps with a good hour walk over a couple of miles or so might yield different results. Second, I do find myself walking taller as the curved sole kind of forces you to walk that way. I don't know if this makes my posture better when I'm not wearing the shoes but it's better than nothing.Skechers has a competing product called Shape-ups which has the same benefits. Not sure if they're accurate or not but MBT was the original so I put more trust in them. Plus, MBT seems to have much better styles to choose from versus the bland cheap tennis shoe styles that Skechers has. If you're looking to take the plunge, head over to Endless.com. I bought my shoes there and the service was great. Prices were much cheaper than buying at a retail store and they have a great return policy and free shipping. I bought the Tembea style which look good both as a hiking or casual wear shoe.