I guess many people do have some bias towards JP voice acting (be it like that because of popularity of anime or whatever) and all things JP anyway.
I've heard some ridiculous JP voice acting aswell as english ones. Still if there is choice between good JP and good english voice acting I think I would go for english (that is if we can assume that lipsynch is perfect for either of these languages, I hate bad lipsynch). The reason I prefer english over japanese is that I can understand all the dialects better which make the game feel more alive for me.
Still, the main reasoning when choosing between english and japanese voice acting in games is the origin of the game basically. Listening english dub on a japanese game is stupid as the lipsynch usually is quite off and it really takes some "reality" away from the game.