We're using the plugin on an education website, and it's really been working out well - thank you for this!
One thing we've noticed is that once we get a fair number of pages in the site, pageloads slow right down. It appears to be related to building the menu on every page load. We have 189 pages in a hierarchical structure, and there is sometimes a several second lag before a page loads. Turning off the widget for this plugin solves the problem (but then we can't navigate the site...)
Do you have any suggestions for possibly caching the menu tree?