I used both Chrome and Firefox about equally. Firefox offers a few more extensions than Chrome does still (I believe you still have to be on beta channel for Chrome add-ons?), but Chrome has an excellent UI and many built-in extensions that nullify the need to install them. I'm currently just running 3 in Chrome - a password vault, a bookmarks manager, and a translator tool. Plus Chrome is fast, though it does get a bit more memory heavy than Firefox. Both, really, are good cross-platform browsers with sufficient support and a plethora of extensions and styling options.
Really Opera is probably a good compromise between the two though I don't really like it. It also is the only one as far as I know that scores 100/100 on the Acid3 test. Then again Fx has a lot of support for HTML 5 already...
But Firefox, Chrome, and Opera are the "best" of the five (the others being IE and Safari).