This is one of the greatest plugins. The main credit is that its made to work without the least bit of problems. My sitemap was submitted within seconds. Before end of the week, About page has started to show up on Google.
I was working with another XML sitemap provider (as it came bundled with their SEO tools etc etc), and even after a week Google Webmaster account did not show any sitemaps registered.
So 5 Stars. I would recommend this to anyone, who is looking for the efficient XML Sitemap plugin which delivers great results.