After trying on many tennis/fitness shoes, I finally found one that's right.  I never found the shape-ups shoes with the rocking bottoms comfortable, and with a bad back I wanted something that had a lot of support, a good arch, and a lot of cushion.  These shoes hold my feet, especially around the heel, and the thick rubber on the bottom absorbs the hard ground against your body.  I did have to go a 1/2 size up, which then fit like a glove.  I'm very happy that I found these shoes!