After working on a MacBook Pro with OSX Snow Leopard for a few months, I almost go into convulsions when I am forced to tolerate the utter inferiority of Microsoft Windows. Don't ask me which version: XP, Vista, or 7 are all just different colors of terrible.
While UNIX was a proven and well-understood operating system (OS) for mini computers, the original PCs were underpowered and had to settle for much less than a real OS. Yet UNIX had captured much critical knowledge about how to succeed at providing access to computer resources. Support for multiple users, connectivity, and the security it would require were accommodated by fundamental design decisions built into its core.
Over years the feature set of Microsoft's OSs have expanded to cover many of the same requirements as UNIX, yet without the same level of consistency and performance as the latter. The Windows OS line is itself probably responsible for more security breaches and real dollar losses expended in dealing with its security issues, than any other OS on the face of the planet.
Steve Jobs made a brilliant move in adopting a UNIX style core for OSX. Are there still flaws? Sure. But you just don't see the time robbing, attention wasting, excessive security risks that you are guaranteed to see under a Windows regime.
They say, "Time is Money,", but really it is worse than that. You will never get back the time you lose dealing with the short comings of the Microsoft platform. Best never to go that way, for down that path lies madness.