We have a variety of city bikes with a variety of IGH's and I do switch around occasionally so get to experience each. I love the N360 and that is on my primary Workcycles Opafiets. That said, anecdotally, I think that it is less efficient than the Nexus and Alfine 8's or Sturmey 3-speed. No idea by how much but I can imagine that on a steep enough climb that you do everyday it'd be noticeable. My limited engineering mind thinks that'd be the case as well with the ball mechanism's likely higher friction in the N360 vs a planetary.