What's to say? This plugin does what it says and does a fantastic job of it. Automatically generates sitemaps and then even notifies Google and Bing for you. The sitemaps are also human-legible which is nice and there are easy control to exclude certain pages from indexing and more. Works out of the box with custom page/post types from things like e-commerce solutions as well.
Highly recommend this plugin if you want to increase your search engine visibility via properly formatted sitemaps.