We're finally transitioning one of our sites over from a single author setup to one in which each contributor can publish his or her own posts. Our file hierarchy is incredibly important, as we're dynamically creating ZIP bundles of each post (text, images, and audio) for visitors to download. Previously I had manually re-named each image prior to upload, but I can't trust our various authors to do this consistently.
This plugin is an absolute godsend! I had tried writing something similar myself, but this plugin covers most contingencies, and is well-written enough that I didn't have a problem integrating it with our platform (I tend to shun any plugins that generate errors in debug.log or result in a performance hit).
I've modified the plugin to include a hackish asynchronous automatic file renaming hook on save, and wrote the plugin author to see if he might consider adding this in an official update. He wrote back within minutes saying it's on the way, so stay tuned!