well i based my opinion on spoiling myself with the japanese. so it's more of a comparison....
aqua's VA was a bit of a dissapointment only because they "localized" her personality, i thought it was perfectly fine how it was in the japanese. that and some other isues with her VAing. but overall, i don't mind too much.
terra, was great. it wasn't much of a localization on his part, it was more of changing it overall. his personallity in the oringal could've fit more, but the VA in this one made him seem much younger and more gullable. so his aspect changed it. those who haven't played the original can easily expect what happens to him from the way he talks, in the english, you sense a different ending, yet near the end you get to see it coming. still, great for not making his story less predictable. still, he could put just a little more force onto some areas. he seems to act similarly to aqua's japanese personality....
ven. he is by far my favorite, although i love the original VA, this time, he's less whiny when he shouts out a name. but even so, the personality of his was easily distinguishable from sora's and roxas's and you can't call ventus "roxas". i'm still on que, but i regret not playing ven first.