I find myself fishing around for the center of a face and at times when there are a number of faces to which the snap could be applied to, I am not sure as to which one actually is being snapped to. I have two suggestions:
One - That the whole face to which the center is snapped is highlighted in some way so that the wrong face is not snapped to by accident when there are many faces to which the snapping could be acting.
Two - That "Stick to Edges" which is a sort of snap-to-the-snap function would work with Center of Face as well. The center would be snapped to any time the mouse was over any portion of that face.
Both these behaviors were present in V6 and snapping to the center of a face was considerably more efficient with them.