Firefox also has an added benefit: It's not tied into the OS.
If something FUBARs Firefox, Firefox can be uninstalled and deleted without causing any damage to the system. A fresh install can then be done, and the trouble ends.
IE, on the other hand, is chained to the file browsing system of Windows. If something screws IE, chances are good that the system itself is in serious trouble. To fix it, a reformat is often necessary.
I can do without that, thanks.