Re: Mouse travel
The Mac menubar's positioning isn't really a large factor in usability to be honest. As pointed out, it being at the top makes it effectively infinitely tall for hitting with a cursor so that's good, but it always sits at the top of whichever screen you nominate as your main one so getting to it can be a real task, which is bad.
There's only one, which makes more compact, which is good. But that means that it's modal, which is bad.
From a subjective point of view, neither of the goods or the bads outweighs the other.
In practice I think it's even less of an issue because people that use computers a lot tend to use keyboard shortcuts anyway. Besides the task specific command+s for save/etc, the best Mac one for the menubar is command+shift+forward slash. That opens the search box in the 'help' pull down, so then you just type the name of the menu bar command you want (or some section of it) and hit enter as a sort of menubar-specific take on quick launchers.