I have been using flock for a little while now, and am pretty impressed to say the least. In fact, I urge you to give it a test run. Visit Flock.com to download it for FREE right now!
Firefox is a browser that I really really like, its fast, easy to use and the amount of great extensions available is insane! The main reason I originally stopped using the very crappy Internet Explorer, is because of the way it rendered CSS in websites I was working on. Basically it did, and in some instances STILL displays the CSS incorrectly, making your well designed websites look crappy! This is NOT a problem with real browsers like Firefox and Flock.