Hello, I appreciate very much your plugin: very simple, we install and nothing to do ^ ^ The sitemap is really full.
In recvanche I'm not convinced not to notify search engines: I did some tests between your plugin and Google XML Sitemap and my items (I have a website on the news) are indexed much faster with this last. Google XML Sitemap that is between 10 and 15 minutes and your sometimes with more than 5 hours.
This is not dramatic but I think you should improve this parameter to be better than Google XML Sitemap.
Last point: in my case I have about 1400 items, your plugin reference all articles (parfait!) but opening the XML file is quite long. I ask myself this question: is it a handicap for some search engines?
Anyway, thank you for your excellent work by apologizing for my bad English.