My feet are slightly wide, so I am never sure about getting the "medium" or the "wide" in running shoes.  For these, I tried the "medium", and it was so narrow I couldn't even tie the laces.  I let them out as far as possible, and they still cramped my toes.

Not a problem, I returned them to Amazon unused, and they sent me the wide-body size in exchange.  Even the "EEE" size is slightly narrow for my feet, which usually means to me that their sizing is off.  It doesn't matter for running shoes, though, because they stretch, and the tight fit is not uncomfortable for the short runs that I do.

These shoes have a lot of heel support.  They seem to be designed to force you to keep your feet straight while you run.  This feels a little odd, but is not uncomfortable.  The mesh is cool, but not too thin, and the plastic is bright, but not so bright that it looks unusual if you decide to wear it with jeans.

I like the arch support, and the heels feel pretty comfortable, so I would buy these again.  The only thing that keeps me from giving these a five-star rating is that the size is a little tight in the toes, and takes some getting used to.  This depends on the shape of your foot, though, and someone else might find them absolutely perfect.