I'm an anime watcher and a firm believer in the fact that if it originates from another country, then listen to it in their native language.  BUT...the subtitles are written for the English audio.  So if you have a moderate grasp of the Japanese language you will get annoyed with the mis-translations that pop up from time to time in the beginning and then more often later in the game.  

The biggest offender? Names.  Myrtle? No, she's Sheri.  Philip? Rick/Riku. 

Also having to read the subtitles based on a Welsh accent while listening to a Kansai dialect is a bit distracting....and annoying when you see "Tidy!" or "En'it" or whatever it is.  It's like Naruto and the "Believe it!" crap. 

But like the others have mentioned, the English voices are superb, and since the subtitles match the English audio I would recommend going with that.  Unless you're ok with the Japanese audio not matching up more than half the time from the subtitles.