The main difference is, I think, more voice acting and different combat special effects. I hate to say this but I like the hand-drawn ones better than the PSP-animated ones. The US audience for this game is definitely those that missed out buying on the GBA, because the game seems otherwise identical.
Wow, for some reason, I always thought that Mikuru from The Melancholy of Haruhi Suzumiya sounded just like the Japanese Cierra. The links above pretty much proved that fact to me now =D
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KITTI IZ 4 FITE (( 彡 彡 彡 ∧ ∧ __ 巛 彡 ⊿彡》 (,,゚Д゚)┻╋╋ ※ ο ο ο ο ο ο 巛 ゞ 彡 ソ彡 / ⊃┛ ̄ _|\│\/\/│_ \( ノ \ ZOMFG / Currently: Not working on the projects I want to finish...