It's mostly the people who take the manga way too seriously that hate the episode. The other people who hated the episode are the art-freaks, but I don't know why. Who cares if the action scenes have sketchy art? The talking scenes in the episode (where art actually does matter) had some of the best art this series has ever had, while the action scenes had some of the best animation this series has ever had.
I'd say this episode easily had the highest budget of any episode that the big 3 Shounen have put out to date (OP/Bleach/Naruto)