I'm currently buying some new USB micro cables for my Samsung Galaxy S5. It supports both USB 2.0 micro and USB 3.0 micro connectors.
Will I see better charging times when using the USB 3.0 cable connected to a wall charger vs. a USB 2.0 cable? I would assume not, but I'm not sure. AFAIK, not too many things draw any more than 2A.