For a while it looked as if Mozilla's Firefox browser was destined to become a huge threat to Internet Explorer in the web browser wars. Firefox has continued to slowly but steadily eat away at IE's market share, and for good reason. In many ways it was just a better overall browser than IE . With many of the same features that helped spark Firefox's popularity as well as its intimate coupling with the Windows Vista operating system, Microsoft's newest browser offering has raised doubts as to whether Mozilla's market share can continue to grow at its current rate.
IE is not using common web standards to display web pages. The dozens and hundreds of CSS-IE work arounds tell their own story and there is definitely no light at the end of this tunnel.
This alone is the best reason for not to use IE since clean coded webpages are not displayed properly.
The second reason to use FireFox is that it is free. Most people might think that IE is free too but this is not the case. IE comes with MS software and this software is neither free nor cheap. FF is a product of a large group of people working together to create a mighty and easy to use browser without any effort to earn money. Everybody is able to join everybody is free to use and share.
Hence there is just no other choice. And best of all these reasons count for every single FF or IE version for the time being.
Firefox, for the most part, is a stable browser. However, even the most stable browsers crash. Firefox has a great feature built in called "Session Restore". In the event of a browser crash or accidental shutdown, you are given the option to restore all the tabs and pages that you had open before the browser prematurely closed. This feature alone makes Firefox very attractive.