Part 1's animation was more consistently good but the artwork was worse.
Now it's just done a complete flip - Part 2's artwork is more consistently good but the animation is a lot less consistent, depending on the animator they pick.
Studio Pierrot have gotten so cheap that they use good animators mostly for only parts of episodes, very rarely paying for them to do whole episodes.
336 was given a decent animator - Masayuki Kouda. He's not as good as Hiroyuki Yamashita (he did 322, Madara's pawnage ep) but he's still one of the better ones.