-really,it's a matter of fighting smart vs fighting hard.sasuke fights hard not smart.naruto fights smart and so does shikamaru and itachi.neji does in theory ,but he's really just a one up character to show how powerful anyone else is,he's not important and never will be.heck,they could kill him off if they want.
-we know sasuke will win because he's a main character and one of kishimoto's babies and it's a shounen anime
While sasuke is much better at ninjutsu,neji doesn't need it much.sasuke beating neji would depend on his ability to use ninjutsu on neji.
here's the problem:they're equally fast and have the same stamina
most likely,the writer would make neji get caught up by the mangekyou sharingan and/or melee'd by jutsu to show how awesome sasuke is (he is).Neji will put up a good fight though.
-if he the plot demanded it,neji could murder sasuke with mild difficulty.becaus neji and sasuke are on par with speed and neji is a defensive fighter,they'd have to get close up to even get anything done.
which is bad for sasuke.hit him with the eight trigrams,no more ninjutsu.hit his heart?he's dead
and don't say sasuke can stop it,the hyuuga fighting style is hard to block and even if he does,his chakra in his arms are still gonna go out from it.hell,he doesn't need that,he just needs to get to his arms then his heart or worse? hit the neck,base of the skull or spine,complete and total paralysis, hell, he could probably hit the points in his head connecting to his eyes and disable the sharingan!
at least in theory...
but where's the fun in that?
-of course,i believe in a naruto style fight ,sasuke would win.it'll be hard,but he will
.and don't say genjutsu,seriously,the byakugan can see chakra points so unless it's plot demanded all hyuugas should be immune to genjutsu.but i don't think they are because then sasuke and all the other sharingan users will have problems. also ,the sharringan copies what it sees,the gentle fist style is good for sneak attacks,the hits blend together
kishimoto style:sasuke wins in practice ,he's like one of the strongest characters in the series and he's ,well sasuke
in theory:with a different writer,neji will f*** sasuke up,bad.he could leave him death,blind and crippled from the neck down
Life or death/asassination: Neji wins,hands down in this catagory.actually,if they sent neji to kill or cripple sasuke a long time ago,it would've save so much trouble,so much pain and suffering
should write it as a fic about it...
but we all know the anime/manga is gonna give it to sasuke anyway.