User Interface, and Apple did a lot of research to get menuing right. They did a real good job, and are still the yardstick with which the others must be measured.
Menus are very efficient, easy to hit, easy to use, and clear.
How Menus work on a Mac With the Mac there is one global menu-bar, that is always at the top of the screen, that changes context based on the front most Application. Yet, Apple's implementation of the architecture is far more powerful than anyone elses. With the Mac you can dramatically change the look and feel of menus. These are the power-users menus. Everything is clear and easy to hit, easy to understand, and easy use.