Firefox 3.5 is my main browser but have been also running the new Google Chrome side by side and will say it's just as fast as Firefox. It does not have all the good stuff like online bookmarks and the tabs options are lacking but in the future I think it will become a very good browser.
Here is a link that can do a much better job of explaining the features of Google Chrome then I can. Firefox is a better browser in that it's been around for awhile and there are lots of apps that will run inside Firefox that Chrome is lacking but Chrome has some pretty neat features and one that I use all the time is where you can pull off a tab and start a new window when you get to much stuff open.