Probably I shouldn't write a review for an add-on like this because I'm a newbie in the SEO field but I think it's important to show gratitude when you find something very useful and somebody worked hard to give a free contribution to the community.
In my small experience, I found tons fo add-ons for SEO with a lot of redundant and useless functions, while they were lacking of relevant features.
In my opinion, hhis add-on has the best and complete range of SEO functions you can look for, with the double advantage for a not expert to discover both the tasks you must know and the tools to perform those ones. Just to mention some of my favourite functions: Google search operators, Alexa traffic, Profile (not even if it's not intuitive to understand its meaning: BuiltWith, NetCraft, OpenSiteExplorer, SEMRush), CopyScape, Tools (especially Search Spider Simulator, that was the reason I tried this add-on).
So, thanks a lot McNulty, you really exceeded the expectations!