There are a few posts and articles around the security-scape lately concluding Windows 7 is more secure than OS X, especially around network based attacks. I tend to think that's true. The culture of security the normal Windows user has is far more mature than that of the average Mac user. Macs hasn't been as targeted - thus far. Also, some of the conclusions around authentication on server processes is that they are broke in OS X. Based on some of the ways I've seen Macs beaten in security contests, I would have to agree with that conclusion. And if we want to compare Safari versus Internet Explorer, there really is no comparison. Safari gets killed at PWN2OWN every year, right from the outset. But I still prefer my MacBook Pro. Huh?
Yup, and it boils down to user experience. I can make the MBP reasonably secure for what I need it for. That doesn't require a tremendous amount of effort, either. Functionality and ease of use wise, the Mac is well ahead. Now count me in the camp that thought I would never like Macs. I remember them from the late 80s and early 90s. I was a lab proctor and admin over them. So I earned my dislike of macs legitimately. But that was then. Nowadays, I find the Mac more intuitive, requiring less steps and effort to do what I typically do on a daily basis outside of SQL Server. Web browsing, documents, manipulating photos, etc., are the typical things which an average user does and it just seems easier on a Mac. For those of us who are power users, we do these things, too. So I want minimal disruption and aggravation from these regular tasks so I can focus on the more intensive tasks.
At the end of the day, security is another consideration to take into account. The circumstances determine it's priority. If I am talking dealing with sensitive information, I may go for a very locked down system with little wiggle room for exploit. But if all I want to do is check the hours of a BBQ joint are near hotel, I will use that hotel provided computer in the business lounge. The key here is to do a proper evaluation of the risk and determine whether or not it is acceptable. And this is why, despite the news that Windows 7 is being considered more secure by the security professionals doing the scrutinizing, you will still see those IT pros using Macs stick with them. This goes for the security professionals, too.