(facepalm) so if you were a water user and i'm a lightning user and you have a string of water leading to me i use chidori stream you would die -_- plus sasuke can absorb lightning and if he creates a field of lightning around him and kisame attack he would die depending on how many volts he send out, & amaterasu owns.
If we want to get all technical then water itself isnt a very good conductor, at least with "normal" voltages. Anything will conduct electricity if the potential difference is high enough. What does conduct electricity are SOLUTIONS, solutions which contain ions, which come from substances that dissolve in the water and dissociate into ions. So pure water not a good conductor water with stuff dissolved in it, good conductor.
Since this is a manga we can't tell it suiton is 'pure' water, so really the debate can't be solved. On the other hand it really comes down to which technique is stronger. This fits well with Narutoverse since this is the basic rule which applies to techniques that don't have a direct elemental relationship (such as water and lightning elements).
At the end of the day it come down to what is stronger and what techniques are used. If Kisame uses water dome jutsu then Sasuke would have to discharge a sh!t load of raiton chakra since water doesn't conduct it very well. Don't forget that Killer Bee is also a raiton user but he didn't use lightning in the dome.
On the other hand most of Kisame's techniques such as shark bullet don't actually physically connect to Kisame so a direct stream between sasuke and kisame is impossible anyway.
