Both browser has their strengths and weaknesses. Its very ignorant to say that FF is better than IE. There are not as many people who want to hack and attack FireFox as they do with IE. IE is beaten badly for many years now. So, its too early to say how secure is FF. Especially, the number of patches they are releasing lately, its really scary. I use IE6,IE7, FF, Opera and Safari for testing. I am still not convinced to use FF for my banking needs.