Word for Mac is almost the perfect evolution of the UI.
It has the menu bar, which every Mac app has since it's a fixed and global UI element. It has the ribbon which is good for many users and makes many tasks easily accessible.
I'm not sure how you'd make this compromise on Windows without making a mess of things, but on the Mac it works very well.
That keep changing and moving about.
I use Word on Mac. It has the ribbon. 90% of the time I use the old style menu bar at the top of the screen.