Like most cooking methods, I've found sous vide to be simply another method to accomplish a desired end product. As has been mentioned, the advantage sous vide offers is transforming a poor beef cut into a taste treat that no one would believe could be so tender, but the rewards are likely not as great when you start with a good cut to begin with. With that said, there is no better method to cook chicken breast to keep it juicy.
The bottom line for me is that I would use sous vide just for fun, or to transform typically difficult cuts into something special.