ya, I also think that the guy on right is a bit over, hehe
For this pic, I actually more interested at their poses and facal expression than the background.
I think you are so right that rather under than over, cuz we still can doing sth with it by using Photoshop or whatever when it was under. But personally (bad habit), I just not quite comfortable with pictures which are under exposure, bcos I love contrast ^_^ I tried the matrix meter before too, normally, it turns out fine for the whole thing; somehow, it happens that the background was fine, but the main object tens to be a bit under... ... headache