Both of my favorite characters are dead, Juraiya and Itachi. Even at a young age Itachi seemed to hold on to the courage of his convictions. Even before the massacre he didn't along with the clan just because they were his clan. He would try to think of what he thought was best for the village. Although I don't agree with his decision to kill his clan, I understand he was in between a rock and a hard place.
Danzo had decided not to wait for Hiruzen to come up with a plan and was going to have the Uchiha slaughtered by Anbu if Itachi wouldn't do it. Itachi's choice was pretty much made for him because he loved his brother so much that he wanted to keep him alive. If Anbu had to do it Danzo said Sasuke would be murdered too. At least his clan was murdered by someone who cared for them and wanted to make it as quick and painless as possible. He was able to admit his mistakes as an edo and tried to make Sasuke understand what he did.
Sasuke on the other hand seems incapable of learning from the past or his mistakes. He seems to go whichever way the wind blows. He was easily manipulated by Oro, Kabuto and Obito. He's heading down the same path as Madara and Obito who thought they knew what's best for everyone. He is more powerful than he has ever been, but he is still a child emotionally striking out at anyone who represents the system to him. All he has done is transfer his hate from Itachi to Naruto and the system.
Until he is capable of allowing some other emotion beside anger and hatred into his life he will end up like Madara and Obito. Both Itachi and Juraiya were flawed, as most people are, they knew their strengths and their weaknesses. Sasuke can't admit to any weaknesses because of his arrogance and he certainly won't entertain the fact that he might be wrong.
Although there have been times when I have liked Sasuke as an entertaining part of the manga, he's just not in Itachi's league.