There are pros and cons for each browser. I have been a Netscape/Mozilla/Firefox advocate since about 1994. I will likely not switch as I have too many customizations with Fx that may not be available with others.
Firefox is an ongoing project developing the FX browser to improve your web experience. If something isnt just right for you, there is likely an add-on that will fix it to your liking.
They are constantly updating to improve security.
IE is losing ground to all the others. They are fixed on implementing Windows but not always focused on what a user wants to accomplish in the browsing world.
There are about 30 differnt browsers - IE, FX, Opera, Google and many others. Pick the one that you are comfortable with.
Supporting information:
http://internet-browser-review.toptenreviews.com/