I use both browsers regularly. I used FireFox on my macbook because let's face it, Safari isn't a good browser at all. But on my desktop I use Google Chrome.
I feel like they both have their perks, I just got a magazine from PC World that ranked the browsers and Chrome came in first for Speed but FireFox came in first for add-ons.
I really think it's all about personal preference and what you plan on doing with the browser, whether it's for just browsing the web or if you want to have a whole bunch of add-ons or not.