A number of tools that aggregate useful SEO-related information on one page can quickly evaluate content and provide instant access to individual sources. Ann Smarty rates six tools. The post offers a description for each, along with a rating of each tools' overall usefulness. She also provides a screen shot so you get a visual of the sites.
The sites deliver a variety of data features, from aggregating tons of data comparing your site with your chosen competitor, to providing a list of related sites such as international resources of similar size, for example. Smarty admits she doesn't use these sites often, but they are convenient when you need a quick SEO overview.