As Dragons said, noise is definitely an issue. But then, even a "quiet" PSU is loud these days considering the higher wattage coming out of it and the bigger fan required to accomodate it. It simply means, quieter for the spec.
Been playing the Beta a bit. Different style of game. I know its a Zombie Survivor and all, and in the feel of something like Dead Rising, but still, having a bit more action would be cool. Of course, theres a long way to go still until its complete.