The difference is mainly (in my case) based on security - Internet explorer is not very safe, it has a track record of being hacked, cracked and hijacked. So I choose Firefox which has a clean history
IE 7 has something called as Phishing filter.
Here are answers to some questions about Internet Explorer Phishing Filter.
What is phishing?
Online phishing (pronounced like the word fishing) is a way to trick computer users into revealing personal or financial information through an e-mail message or website. A common online phishing scam starts with an e-mail message that looks like an official notice from a trusted source, such as a bank, credit card company, or reputable online merchant. In the e-mail message, recipients are directed to a fraudulent website where they are asked to provide personal information, such as an account number or password. This information is then usually used for identity theft.
What is Phishing Filter and how can it help protect us?
Phishing Filter is a feature in Internet Explorer that helps detect phishing websites. Phishing Filter uses three methods to help protect you from phishing scams. First, it compares the addresses of websites you visit against a list of sites reported to Microsoft as legitimate. This list is stored on your computer. Second, it helps analyze the sites you visit to see if they have the characteristics common to a phishing website. Third, with your consent, Phishing Filter sends some website addresses to Microsoft to be further checked against a frequently updated list of reported phishing websites.
If the site you are visiting is on the list of reported phishing websites, Internet Explorer will display a warning webpage and a notification on the Address bar. From the warning webpage, you can continue or close the page. If the website contains characteristics common to a phishing site but isn't on the list, Internet Explorer will only notify you in the Address bar that it might possibly be a phishing website.