I just tried this after running into problems with some of the other commenting extensions for 1.5. Very easy to get up and running, and very simple to use. It doesn't overwhelm you with options, but that can be an advantage. The parameters aren't always intuitive, but once you figure them out, you realize the extension gives you more control than you first thought. Also, since it tracks comments in Joomla articles/categories/sections, you can use content modules to view latest comments, etc. Very nice feature.