mhhh english voices, so far for me:
Lightning: perfect
Serah: good
Snow: good most of the time (romantic scene kinda meh)
Hope: a bit strange/ sounds too old
Vanille: good (for such a cheerful character)
Sazh: good
Rosch: kinda bad (the loud parts sound like a generic bad guy + forced voice)
Jihl: good
hot new chick: wtf, the accent, she's ruined? D:
So I prefer Snow, Hope, Rosh and new chick in the Japanese VA.
Lightning, Vanille and most of all Sazh in the English VA
Serah and Jihl both sound like they should (based on my impression of the characters) in both versions.
also the "oh, ah, uh"s sound more natural in the Japanese VA :lol
I'm not so sure about the actual script, seems to be very different sometimes from the original (I base that on the gametrailer subbed version which I assume was translated more directly). Some lipsyncing-problems, especially in the romantic scene at the beginning (e.g. when Snow's laughing, sounds like his mouth should be wide open. He's not really laughing in the Japanese VA)
btw I don't get the scene when Serah is captured or something, she did it on purpose while still reaching for Snow? May be a cut.