Firefox is the best, oh really ? -Zdnet
IE doesn't follow all standards and thats coz, Microsoft chose to make IE fit the code developers produced, however non-standard, so that compatibility with IE involved little extra work. There is see no reason why we shouldn't expect the same of alternative browsers such as Firefox.
Hmmm..Think of the long term benefits...think,think and you will have the answer.

Firefox is probably a safer security bet than IE. Don't be lulled, however, into a false sense of complacency. Firefox certainly doesn't use Browser Helper Objects, a technology misused by "spyware" vendors to monitor where a user goes on the internet. On the other hand, it's not true that Firefox isn't extensible. Binary installers (the standard way Browser Helper Objects find their way onto a Windows system) can install Firefox extensions just as easily as they install IE extensions. In other words, the reason Firefox doesn't face the threats IE faces is that they aren't the browser used by 95% of consumers.
This is where open-source chips in. There are certainly more developers contributing to Mozilla than IE, and more the developers, better the results. Why I don't recommend Firefox by Adam Kalsey is also a nice read. He basically highlights the interface and marketing problems with Firefox.