The raw representation is a somewhat cluttered (to the untrained eye, anyway) json file - especially if you have checkpointed images which are bascially base64 encoded blobs! So as far as I know it's pretty much the web-editor or nothing at the moment. Obviously a JSON-aware plug-in for something like PyDev or Pycharm would be pretty neat, but I think we're a ways off that. See also http://nbdiff.org/ which solves the issue of comparing version-tracked notebooks.