@bloodline
That's fine that you consider the audio system mission critical for your work. What I am looking for is an objective reason that MacOSX is technically better than Windows XP/Vista. You said latency which is subjective, and crashes which sound like operator error, a bad computer, or just FUD (every OS can crash..). If you had proof that the same audio hardware on like systems, one running Windows and one running OSX, ran differently then I might take it a bit more serious. The "99% of all professional musicians use MacOSX" falls in the same category. It sounds too made up to be true. Care to site a source?
Regarding your security comment, you don't really know Windows. Windows 9x had a single user security model. NT and later all have separate roles for user and administrator. In the end, if the operator chooses to run as root they can do so just like they can in OSX. Vista has the UAC which is similar to the OSX prompt when root access is required.