Being mostly US dominated, I don't think you'll get a definitive answer. You might want to try the UK forum! But even then, I think you'll get mixed answers of yes and no.
Therefore, I think the best idea is to use a tank of regular diesel and then a tank of V-Power and see if there is a difference. Then do the sums yourself, plus any qualitative factors such as improved throttle response. Then you'll have your answer! I did try this in my old 330d and although the response was very marginally quicker, it wasn't enough to make me think twice about shelling (pun intended) the extra cash for V-Power. MPG was negligible. The cost was astronomical. But the 2009 N57 30d and 2012 N47 20d EfficientDynamics are two very different engines, so you may see greater improvement!
2006 BMW E60 520d SE 6MT
2009 BMW E90-LCI 330d SE 6MT
Current: 2012 F30 328i Luxury 8AT
2015 Audi A6 Avant Ultra, Black Edition (sorry!)