I seem to remember some discussions in the mid-nineties when the 777 was introduced into the BA World Wide Fleet. There was a 777 "phenomenon" that seemed to affect some crew but could not be actually traced to anything. I know when the aircraft turns, you sometimes feel a "sweeping" motion which can be unpleasant when standing. Personally, I have never had any problems with the 777 and much prefer it to the 747 (apart from the First Cabin, which is much better on the 747).