Sometimes Dubs are really really great. Like in the original VHS Akira, or in DBZ, or Gundam, cowboy bebop, samurai champloo, Inuyasha, etc

At other times they aren't good at all, like in Naruto, bleach, witch hunter robin, DVD Akira, and the vast majority of other anime

It's hard to say really. 

If the dubs are great, then great, but it's really better to just internationally release with subs, and then release a dubbed version later on. I think it's important to test out dubs first on an american, or english network, for example cartoon network's adult swim, or scifi channel before releasing a dubbed version.

Original audio only...I'll go even the undub way if possible to make that happen. I hate dubs, and I'm of the thought that games (and movies) are made to be played with the audio the creators thought for it