Itachi is a prodigy. More naturally skilled than both obito & sasgay combined from the start. Being trained by madara & taught more uchiha techniques &/or even the little things would do just that much more to show his superiority over them both. --- You're now in the presence of the #1 Sakura Haruno Fan. http://i.minus.com/iwFojp6Ht0gBI.jpg ...Praise The #1 Kunoichi
obito has the most broken sharingan. plus he would have both if madara was to train them from age seven so he would be haxed beyond belief. --- "a smile is the easiest way out of a difficult situation." psn: judefakoyen10
Itachi would show the most potential out of the three, especially if he wasn't scarred by the events of the 3rd great ninja war. Sasuke on the other has greater chakra reserves compared to Itachi and may utilize Madara's training better. We already seen what Madara''s influence has done for Obito.