Though the promise of Marina & Houko in the Japanese voices tempted me to turn on the Japanese, I ended keeping the English dubs on and I'm liking it. The dub cast does a great job, especially compared to Sega's typical lackluster dubs, and it's much easier to pick out a favorite quote when you can understand it.
Generally speaking I stick to Japanese voices. Since they seem to take the position more seriously, and give better acting that English voice actors. That said, I usually play games in English, just so I can pay attention to other things going on. =P