The main difference between IE and Firefox browsers is security. IE has been a focus for security attacks. Microsoft is usually a bit late on counter acting these attacks. Firefox is safer than IE. It loads slower than IE, but once loaded is faster. Firefox has over 2000 free add-ons. I recently switched from IE to Firefox and have been very happy that I did. The AdBlock plus add-on alone makes the switch worth it.
Definitely Firefox its so much more secure than IE and plus the free add ons add more protection, security and tools to the browser.
haven't had my homepage hijacked since I've been using firefox. That is worth the installation. If you add the "navigation sound" extension, firefox will sound like internet explorer. I haven't used internet explorer in 2 years and don't miss it.