Compare Web Searching!

Web searchers - some like Google and some like Yahoo search. Which one is better should be left on the searcher's discretion.
But if one really wants to compare the search results of Google and Yahoo then my friend Swapnil has a new solution. He pointed me a this interesting site which compares the search results of these search engines. Just check it out....
I just wonder whether any of you guys have checked the clustering engine vivisimo!!