Security:
Firefox is more secure because it's security model is vastly more secure than IE. Major exploits are patched rather quickly, especially compared to the time it takes MS to patch IE.
It is also not as tied into the OS, which helps security.
Lacks ActiveX, which is the delivery mechanism for many malware. The article claims that IE SP2 is as good as Firefox in terms of spyware resistance, because
1) you can remove the spyware AFTER it gets on your computer
Yeah, but that's like saying a home is fire resistant because firefighters can come and put out fires. How is that security? That's cleanup made necessary by bad security.
2) it can be made more resistant by following a few steps
Do you expect the average user to take more steps to improve security? Why isn't it secure by default? If it's less secure by default then it is less secure for the average user.
They left out the part about turning up the IE security settings. I guess that's unnecessary?
Sure, with more marketshare there may be more holes found, but there is far more to security than marketshare.
The blog post claims that Firefox has less than 100% security. I fail to find anyone claiming it has 100% security, so nice strawman right there.
Also he claims that Firefox 1.X has a significant number of vulnerabilites given the amount of time that it has been out, totally ignoring the severity of the holes.
Rendering:
Point me to one major site that has major problems rendering in Firefox.
Performance:
Firefox has much better performance than the average user's malware infested browser. Or that doesn't count?
