For some reason in Mac OS, if an application does not have the focus, you would have to click twice on it to get something done. The first click will give the application the focus and the second will do what you where intending to do in the first click. In windows this is not true so for someone coming from Windows, like me, this is particularly annoying. Nonetheless it is not the end of the world.
Mac OS is definitely faster than windows for the kind of work I do on it. I am just finding it a little bit tricky to get use to its windowing system.
It could be the case that, for someone with little or no computer experience; getting use to this kind of things would be easier than it is for someone coming from a different OS.