Firefox and Google Chrome are arguably the best two Internet browsers on the market.
Both of these browsers have a wealth of features and are very stable and secure. I would say when it comes to the full package as far as features and convenience that Firefox is the best one. As far as stability and simplicity, Google Chrome will win.
When choosing an internet browser you should choose it based on your needs. If you are pretty straight forward in your internet surfing than I would suggest going with Chrome. If you like to use a ton of add ons and extensions than Firefox is your ticket. The difference with these browsers is at a minimum. If you are using add ons go with Firefox, if not go with Google Chrome. The bottom line is that you can not go wrong with neither of these browsers because they are both much better than Internet Explorer. I must mention that Apples Safari is a great browser as well, some where between Firefox and Chrome.