Just had a quick look at Neal Martin's Wine-Journal
and found him making the excellent point that 91 is really not a bad Medoc vintage. I was a bit surprised to find him running down Langoa Barton, at least versus Leoville of that ilk in this vintage. Having had both recently myself I would say the Leoville is good if slightly chunky but the Langoa is actually better - a rather fine classic Claret.
Neal knows his Bordeaux of course, so I would guess this is just another example of how storage conditions are so important even for wines of this sort of age. So the question is, is it his Langoa or my Leoville that could be better?