This plugin works fine with what might be considered a "reasonable" number of entries, but as I increased the number of elements--it began to slow down--and now with 186 third-level elements, it refuses to add any more.
The plug-in developer blames the webhost. I've spent hours with the webhost trying various fixes I've found around the web, but none have worked.
I suppose this plugin is satisfactory with a limited number of elements but based on my experience, I can't recommend it if your needs are for elements up into the hundreds. Alas there doesn't seem to be any plugin that will do what I need.