Very useful, will save you time and hassle. You can customize your site maps and once set up you can automatically send them to search engines. The main extension I am using was not available in the predefined data sources, but John included it within a couple of hours and even helped me set it up. Great extension and support.
I tried many different extensions before deciding on this one, it includes some amazing features for your web-site and is updated regularly with new ones, keeping you up to date with the latest trends. The support is great, you also have clear documentation explaining everything which is very helpful if you are a novice like me! Thanks guys!