At least talking about the JavaScript engine efficiency. Sputnik is a comprehensive series of performance tests to measure the quality of the engine each of the browsers. This test kit was developed by Google to help developers build better software, better interpret the orders when faced with a script on a Web page. When testing with Sputnik it was determined that Opera is the browser with fewer errors, followed closely by Safari. This means that both browsers beat Chrome in tests developed by Google, is like giving a taste of his own medicine.

Firefox comes back and finally is Internet Explorer 9, located in a pre-alpha version, so these results do not reflect at all what will be once it is completed the Microsoft browser. These tests were run on Windows with the latest versions of each browser.

Link Official Google Blog
Via TechCrunch