I use both, actually. So I can realistically compare them side by side. As a web developer, its good to test out your pages in multiple browsers anyway. They don't all render your page the same way.
On some computers I have IE, and others I have FireFox (IE is still there, I just rarely use it on machines where I have FireFox installed). The extensions in FireFox are wonderful and part of the reason why I use FireFox on some of my machines. IE works great too and most of my visitors use IE, so I also browse my website in IE too.
As far as the person who said they are loyal to Microsoft. Well, I'm about as loyal to Microsoft as they are to me. I use their products that are good and affordable, and I use alternate products when they are good and affordable. I try to get the best value for my money, and get the best solution for the task at hand. Sometimes Microsoft wins, sometimes it doesn't. I'm not one of those who picks a camp and is blinded by the propaganda. Microsoft does make some good stuff... they also have made some real crap... and sometimes it just isn't what I need and someone else makes something better.
I'm impressed with FireFox about as much as I am impressed with IE. Both have some strong points, but neither are really superior in my mind. Both have benefits and drawbacks. Maybe that's why I use both, so I can take advantage of the benefits of both. :)
Edited by wistex - 13 April 2006 at 10:33am