I'm going to go with Japanese. Granted I can understand a fair bit and will probably understand the cutscenes, I still always prefer Japanese over English. Not saying there is anything wrong with the English voices, from what we've heard, they're pretty good.
However, whenever they dub things, the character always comes out different. Like in Awakening, I listened to both English and Japanese, and the most notable person who changed was Sumia. In the Japanese dub (even with English dialogue) she was a silly, clumsy girl who messed everything up. In English she came out to be a stronger character (which isn't a bad thing) and had more attitude. I remember reading it somewhere, but it's because of the different societies of eastern and western countries and how people are portrayed.
I like the Japanese voices better because we get a sense of what the character really is like before localization.