This is interesting. RustySearch allows a "search engine blind test". You enter your keyword, and it queries - in random - one of Google, Yahoo, MSN, and Ask Jeeves. It then displays the results, and allows you to rate them (1 to 5) - without telling you which engine it came from. Results from all engines are using the same template.
There are also initial results (they are not displayed in real time), after 5,000 votes:
1. Yahoo (3.4287)
2. Google (3.3668)
3. Ask Jeeves (3.2602)
4. MSN Search (3.0855)