Well this is my opinion: Shigure wins
Why? Well simple so far all of you instantly assumed that Shigure would get shocked when he would be hit by water. You didn't even question that but in my opinion that is not true, he doesn't get shocked. Which leads to that he would just pierce through the water jutsu and hit Kirabi who would have no time left to counter and thus looses.
Why would Shigure not get shocked? First and for all the lightning armour is an S-rank lightning and Kirabi used a C-rank water, though of course that doesn't say much. Second and more importantly there's a reason as why it's called an armour, it provides protection. That armour is made out of highely dense lightning and user is completely covered in it. Can you explain to me how it is possible that a highely dense S-rank lightning armour can be pierced by a C-rank water jutsu? yes the water has to pierce the armour. Water indeed conducts electricity, however it's only dangerous if you actually touch it and when does Shigure touch the electrified water? Never as the lightning armour forms a barrier between the shocked water and him. Yes the lightning would in the least electrify the water around the armour, but it would be a centrifugal force with Shigure as the middle.
It has been proven that the lightning armour is incredibly dense and strong: Sasuke used a Chidori/Raikiri on it and it barely pierced it and it was an A/S rank lightning jutsu. If that can't penetrate it a C-rank water jutsu would?
Short said Shigure wins because he doesn't get shocked as even though the water is electrified, it doesn't touch him, so there is no problem. He wouldn't have air for some seconds and the water would cause some opposing pressure, but not that much, thus Shigure would just go straight through it and hit Kirabi.
Hasashi brought a similar example: Sasuke uses a Chidori to control Kirin, but normally he should be shocked himself by Kirin, though the Chidori covers his hand, he doesn't touch Kirin directly. It's not entirely the same, though pretty similar.
If Shigure first would be wet and then uses the lightning armour he indeed would be shocked as then he does touch the electrified water, but when it's the other way around it doesn't work. If it did you could just use a water gun toy to defeat the lightning armour.
Of course you can start debating about my opinion, but then you will have to prove he does touches the electrified water and if you can't do that it's futile.
Some other additional notes
* Shigure's speed isn't that fast. People often assume that each gate increases the users speed tremendously, but that's wrong. It's only starting from the 4th gate that you truly get an enormous speed boost, the first three gates don't increase the speed much, they mainly take away the limitations of the body. Also the description of his 2nd jutsu says he focuses chakra slowly, so there is certainly enough time for Kirabi to act.
* In the case you would accept that Shigure is shocked, I have would said Kirabi won. There would be some momentum in Shigure, however from the point Shigure is shocked he stops running and it's impossible to say which way he's going to fly due to his momentum. For the same money he flies strait on Kirabi or directly into the ground. Considering there was some reasonable amount of time Kirabi would have had some distance of the water. Though as I don't believe Shigure gest shocked I say he wins.