There's one thing that's bugging me that people need to understand:
Animation doesn't mean how well it's drawn.

It's the art. Animation is the movement of the frames. The animation is fantastic because the movement is so fluent. Why do you think people call GIF files 'animated GIFs'. Well, the obvious answer would be that they're animated! You wouldn't said that the animation of a JPEG file is horrible, now would you?

Secondly, I didn't find the art bad at all. It suited the situations perfectly. When the two of them were still and you were just staring at their faces, the art was well done and detailed. Then when they were going all super-fast, the detail level was toned down because you were viewing that cell for a fraction of a second. Then I've heard a few people complain that Sasuke looks "rediculous" when Naruto repeled his fire attack (Fire is so dependable in this anime, isn't it?) with chakra. It's the same chakra 'sweep' move he used in the very beginning to blow Sasuke off guard except a great deal stronger, thus smashing his face in the same way as if you were to stick your face in a leaf blower. Go ahead. I encourage you to try it if you don't believe me.

All-in-all, I thought this was the best fight in the series. Art quality doesn't bother me when the action is so intense.