I know this may be a paranoid question to ask but I just wanted to make sure. Is there any difference between the newer USB cords with the shorter plug (the end that goes into the iPhone) and the older ones with the bigger, square-shaped plugs? Like, difference in transfer speed, or reliability, or build quality? Just asking cuz the newer USB cord that came with my iPhone 3GS is getting frayed and so I'm using the older one instead. Thanks to whoever helps.