Itachi wins, his edo can easily be taken down. One of the ways to cancel the technique is to use the release during a genjutsu. Which Itachi so happens to be a master at. Itachi is known for his powerful genjutsus. This will not only release the current summoning but also the others as well. Once the technique is gone, Kabuto is in a 1 vs 1 fight. In a fight like that Itachi could win easily. Kabuto would be beaten.
It would also take time for the other summonings to protect Kabuto. The other summonings are all busy fighting and Kabuto would have to have other dead ninja just hanging around, already prepared. He does have White Zetsu spores attached to him, which could help, but Naruto has shown that they are not a hard opponent.
I do think that Kishimoto will some how have Itachi die. Only because it would be to convenient for Itachi to be back. Itachi has handed Sauske over to Naruto. By this info, I concluded that he is prepared to die. I just ope Kishimoto makes it a good last battle.