Ok I smell a lot of fanboyism here... So I'm going to be neutral, because I don't like the Sannins neither the Uchiha brothers.
First of all, let's not underestimate Tsunade, after all she was a Legendary Sannin too, and if she was beaten by Kabuto it was cause of her haemophobia.
Also, where is going Sasuke, a little 16 year old boy who has an equal amount of ego as fans. Ok, he did beat Oro but in a weaken state, he should have fought him his prime time.
Itachi... yes he is pretty strong, I admit, even at the same level as the strongest characters in the series.
For the ones who said something like... 2x totsuga swords, there is only 1, Sasuke hasn't got it.
Also, Sasuke's genjutsu isn't at the same level as Itachi's, his Tsukuyomi is a far cry from Itachi's.
Amaterasu is not a deal for Oro, remember the shedding jutsu, also Tsunade has high skill evasion and can protect her with stones by smashing the ground.
Jiraiya is the only one who could have problems with it.
Being the legendary Sannin and having a lot of experience, they have to know how to deal with genjutsu.
They also have all their summonings, that can help out for most things.
I think the Sannins win.