@One_Piece_God: Nagato doesn't have low mobility at all, he was keeping up with Bee and Naruto. Make sure you know what version you're talking about first.
And as omgwhy said, the byakugan/sharingan thing is trash. It was never referred to ever again and absolutely nothing has proven a link between the two. And we know for a fact that the rinnegan is superior to the sharingan and the mangekyou sharingan. If a sharingan can see through most genjutsu, and a mangekyou can see through nearly any visual jutsu, surely it follows that the rinnegan is all but immune to visual genjutsu?
And yes, the toad song worked; but that was an extremely high level technique (arguably greater than tsukuyomi) and it was not a visual genjutsu; you cannot 'see' through sound. And before you say "but they work the same way", think back to the Kabutomaru fight.
Audio genjutsu and visual genjutsu are two very different things. Therefore the frog song working on Pain is totally legit.
Sorry dude, Itachi just isn't winning this one. You could give him Sasuke as backup and I could still see it going either way.