Of the two tools, the SunSpider is more comprehensive and it takes longer to finish and the results are more consistent. Kane’s test runs under one second and the results are not that consistent, which is understandable, because a slight hiccup of network condition could affect the results.
I ran these two benchmarks on my test Ferrari 3400 laptop running Windows 7 Beta. Here are the results.
The other way to measure browser’s performance is by measuring the CSS rendering speed. Here is the link.
CSS Rendering Benchmark
The file is just a plain html file, you can save it on your computer and run it locally. I cannot get consistent results out of this test, so I didn’t post the results.
Do you have other benchmark tools that you want to share? Please tell us in the comments section.
[Update: 3/19/2009] Another popular benchmark tool
V8 Benchmark Suite