I like that you can find almost any book related to marketing or SEO, there is nothing for me dislikes about this product it's good! It helps us learn more content management system better than others because we have many options of tools here :).
If i were not sure if will be usefull -i do recommend using other products before buying- but when your thinking what tool should help best? Go into webmaster world forum/community etc.- get some advice from people who know them very well (like myself)- check prices compared by yourself.