Which story do you think is better? explain why?

It depends if you wish to be practical or believe in the myth. I agree with you, the mythic story is much more interesting. The animals on Pi's little boat can be said to represent different parts of Pi. Pi is a complex little boy, his thoughts swirl the metaphysical and the corporal. The conversations he has with the animals are similar to the questions that we all ask about life. The food chain, the natural hierarchy and our place in it all is at the heart of Pi's tale.

The animal story is better but I think it was made up by the boy to try to hide the horror of the true story. He made up a story to save his sanity and humanity.