These shoes cushion your feet, a lot.  After becoming accustomed to them, I am more comfortable in them than any other shoe or barefoot.  I am going to purchase a pair of skechers that are more breathable for spring/summer as these are going to be too hot to wear all day.  I do wear them all day, and don't want to take them off when I get home from work, except my feet are hot.
I have a wide foot, but did not buy wide width size, and the shoe fit fine.  Pretty much true to size on this style (motivation I think is the style I bought)
I do not know if they helped shape or tone muscles or if they helped me lose weight, but if they are as comfortable on you as they are to me, they are worth the price.  I have lost a little but cannot definitively credit the shoes for it.
If balance is an issue, you want to be careful.  I am not very coordinated, & I have not tripped or anything.  I do find myself rocking to catch my balance while doing tasks around the house.  No trouble while walking.  I do not run or do heavy workouts, but these shoes make walking fun.  I feel bouncy.  They also add height, but are not at all like high heel shoes.