I'd book-marked it but I've only dipped into some of the tools. I seem to recall that some of those I tried either didn't work or threw up some odd results. However, some of the tools throw us some nice, "Did you know?" type questions.
For instance, did you know, according to
SEO Chat's keyword difficulty check tool, that it is easier to get your keyword "sex" (difficulty factor 87.02%) to appear on the first page of a SERP (unspecified), than it is to have your keyword, "travel" appear (difficulty factor 94.42%). Which means that if you're in the sex-tourism business and want a front page internet presence, you've got a tough job on your hands. (Incidentally, "
SEO" has a difficulty factor of 79.96%).