Part 1 by far.
Sasuke's "revolution" never really grasped me in VOTE2 but in VOTE1 I could completely understand where he was coming from. His family was slaughtered and he wanted to avenge them in any way possible. I would do the same! I could also totally see why Naruto wanted to save him because he could relate to the loneliness and pain. It made me so emotionally torn between the two, which was what the fight was all about. I also must add that in VOTE1 their friendship had just fallen apart, which made their emotions a lot more in-the-moment and raw. In VOTE2 everything felt more emotionally one-sided; like Sasuke was just not thinking clearly and you were supposed to listen to Naruto.
I also liked the fight choreography in VOTE1 a lot more. Naruto's use of clones was a lot more interesting, Sasuke used way more impressive taijutsu, and they're transformations were much more evil and scary looking. The fight choreography was just more viscious, which in turn gave a lot more tension. I'm also just not a fan of the monster battles where they hide in their avatars. It's not as satisfying or personal as seeing them going face to face.