I have installed and used this very fast and easy. It does what it says, but there is one thing one should be aware of: This extension stores the full file path in a mysql database. That means, if your web directory changes, you change the domain name of any folder in the current path, you need to adjust maybe 1000 entries in your mysql db. It would be better to take the basepath out of joomla (or a options setting of the component) and just store the filename of the attachent.
Besides that it´s a great component and very easy to use.
There is a command "Regenerate attachment system filenames" in the Attachments Utilities that does this for you in one easy step.