I've painted a pretty bleak picture of Linux operational security. Due to its development model, it's difficult to determine the future of the operating system, and maintaining it can be a chore. However, Linux has a great number of features and outstanding programs that are very useful in many operations. So, while there may be a tradeoff between security and utility, Linux is often a tenable situation.
When choosing an operating system for use in your enterprise, you need to look beyond the security capabilities "on the box" and think about how the OS really affects you over the long haul. You need to be prepared for the patching, upgrading, and maintenance issues each OS has and understand how these activities affect your security and availability. Ultimately, the enterprise operating systems discussed in this article are very advanced pieces of software that enable businesses around the world to perform IT functions. What works for you may not be what works for your neighbor, but you need to be aware that security for each of these operating systems is a complex issue requiring as much diligence as any other software selection in your enterprise.