I'm curious to understand a little better, if you'll indulge me.  The announcement page claims that the B+ has "better hotplug and overcurrent behaviour" with regard to USB.

Most of the USB issues I've heard of with the Pi seem to relate to power and current, and it would seem that it's being claimed they've been addressed to some degree.  Are there different USB issues, or did they fail to address them sufficiently in the B+?