if I understand what you are saying about the top menu, you're stating that the ability to have unlimited menu items in a single menu is great???
You have to be kidding! When have you ever run out of space for a menu? If your menu has that many items in it, I suspect there is something very wrong.
I may have completely misunderstood what you meant (I hope I did).
On the other hand, having the single menu at the top means that the menu is not explicitly linked to the program window. In Mac it is possible (though I haven't done it yet) to save a file, from the wrong window, as it is easy to get confused as to which is the 'active' window.
I think the top menu bar is exactly the kind of thing I'm referring to when I say it keeps the mac pretty, but not necessarily functional. It keeps the menus in a highly ignored location so the features of a program don't mess with the clean look of the window.