Well everyone is using what Sasuke has shown so far but you have to remember how Sasuke and Itachi both handled Kabuto, Itachi did more work in his calculation and team work while Sasuke was a supporting character. Sasuke's analysis skills haven't been at it's best, that's why I like Hebi Sasuke the best, he used strategies while MS Sasuke would charge and spam. It Sasuke starts fighting like he use too then he'll win but as of now, Itachi can when.
I see people are basing tis on power when Itachi shown to beat people who have more power than him. Enton, Arrows, swords can all be blocked with Yata and Itachi have the MS+speed to dodge them depending on distance. Sasuke's speed never increased, only his reading moves/jutsus so he's not going to be blitzing, as for Kenjutsu, Itachi took Sasuke sword and used it for himself and had a sword at 13 so I'll say they're even with that.
Itachi being able to use shadow clones might give him an edge as well. He can attack from behind Sasuke.
