I have a new hammer toe problem compounded by limited padding on the balls of my feet and needed a shoe to help take the pressure off the front of my foot.  My podiatrist recommended a round-bottom sneaker.  These Shape-ups are a good starter shoe at a low cost and do help somewhat improve my problem.  However I will likely graduate to the MBT.

The Pros of this LIV-Smart:  lightweight and breathable, reasonable price, good looking for a sneaker, helps better distribute your weight while walking, and does improve your body posture while wearing them.

Con (sort of):  the toe box is a bit too flexible (meaning there's less support for the front part of your foot) and is the least supportive part of the shoe.  If you are walking for exercise, this means as your stride rolls from heel to toe, the front of the shoe bends somewhat, which doesn't happen in a true curved bottom shoe.  But this action actually helps make the shoe easier to adapt to for first-time users.  The MBTs on the other hand require a user breaking-in period and can be awkward to get used to.

Update:  I've had these shoes for two months now and as a result of wearing them the majority of the time, both as every-day and walking shoes, they have absolutely helped my hammer toe problem.  I am purchasing a second pair.