I, too, was confused when Medela double pump mini-electric came out and
wondered why it was not as good as the PNS.  Only difference is that PNS is
made to last longer.  Both Mini-electrics have the same engines which are
smaller than the one used in the PNS.  So, if a mom is going back to work,
pumping for a long time, and wants a pump to be functional for other children
that come along someday, PNS is the way to go.