GUI stuff typically gets introduced broadly by many developers across a broad range of applications and finds its way into operating systems through common usage supported by positive reviews and feedback. Neither Apple nor Microsoft invented these ideas, just implemented them in an OS. The really important point to make here is that Mac OS X is a UNIX based operating system, and Windows is not. UNIX has a long track record in many areas of superior performance and security that MS is just not going to be able to match. The Mac GUI makes it easy to use, unlike my SUN workstation with the Terminal command line I use at the office. So get over the Vista interface, it's still Windows. And Tiger or whatever comes next is still UNIX, and that's what sets it apart.
Vista=Copy of OS X