I know that some people don't like these shoes because of the lack of heel support, but that is the whole point in these shoes... a lack of support is more natural.
These are awesome minimalist shoes, with enough but not much grip so that you can move around easily.
The bottom is bendy so that certain angles of the foot are easier to hold, like when doing forward splits or tiptoes.
Running in these can hurt your heel, because you need to run differently, look into barefoot running, or chi running.
I love these shoes, there are just 2 small downsides, I had to change these for a smaller size because they are not padded on the inside, there are charts online that use the size of the foot instead of the shoe size, use them, the other downside is that the bottom goes black/dirty looking fast, but come on... it's the bottom of the shoe.
These are much better than more expensive similar shoes.