Does exactly what it says on the tin, activate the plugin, set a couple of easy to understand parameters and you are good to go.
Ease of use
Automatically enters description and keywords when you save an article, has a setting for number of keywords and a "black list" of words.
Not really needed the plugin is self explanatory
Value for money
Excellent value for money - especially when if you represent a Not for Profit Organization or have a non paying site.