Yes & no or maybe marginally. It seems like many hubs are smooth but the wheels don't necessarily have "kick ass" speed. I have heard hub having high flanges adding some sort of stiffness? Mavic Ksyriums use a Zicral alloy that make them noticeably stiffer than your average wheel. I haven't ridden Zipps or Hed wheels but I'm sure they use their own strategies for achieving power transfer responsiveness...