On a given day, I may use three different browsers for various reasons. Sometimes one browser just gets the job done better than another. Having said that, the following results are only from one test (SunSpider), on one computer (mine), on one operating system (Kubuntu). Results may vary for you, but the point of it is to demonstrate that the browser wars are getting very competitive. On a given day, one build of Chrome may be faster than Firefox, and on another day, the opposite may be true.
On Kubuntu 11.04, I pitted Chromium 11.0.696.57 (82915) vs. Firefox 4.0 vs. Rekonq 0.7.0 vs. Opera 11.10, all on KDE 4.6.2. For obvious reasons, Microsoft Internet Explorer was not invited to this little shindig.
For the SunSpider tests, the results were as follows:
1. Firefox 372.3 ms
2. Opera 438.1 ms
3. Chromium 453.0 ms
4. Rekonq 611.4 ms
(Note: Lower is better in these tests)
As time goes on, I may post more observations.