Nice tool. Could help people with checking up on competitors. Personally think the actual sites looks a little bland in overall theme but that said its mainly the functioning of the site that will actually attract people there.
I'm sorry, but I'm not that impressed. All the numbers in the world won't account for where a site lands for a specific keyword, what the language is when the result hits (description, etc) is it a call to action? and does it compel searchers to click on it. Does the new site create an increase in unique visitors, does it convert the visitors at a higher rate than the previous site? Those are the only stats that really matter. No offense, but I've never gotten into the whole page rank, alexarank back links, load time - they are useful to the point of measuring progress, but the only stats that count are higher rankings (first page is the only page that counts), more visitors and higher conversions.