I agree that could get dizzying. If you can glue the menubar for a given application on top of the application, that would be ok. But the system-wide menu bar hopping around like that would be a problem.
I'm biased to the "menu in app" design that other GUIs offer, personally. I think it just makes more sense. And no, I don't just mean Windows
All the Unix/Linux offerings use the same model.