Why, Sanzaru, have you removed the beauty that is cel-shaded from the Vita edition of this game? I imagine it's only because the file size would drastically increase, but then again, I don't really know. This is a real shame. I was really hoping to play most of this game on my amazing Vita. But it looks like that's not going to happen.
I imagine that is the main reason for the difference in size between the two versions.
The PS3 version is nearly 17GB, while the Vita version is less than 4GB. And quite honestly, I am enjoying the game so much that I haven't really noticed the 'downgrade' in visual quality going from the PS3 to the Vita.