The one with the bigger fan, the OCZ may be better. I say this, because the power supply actually believe it or not, tends to be the loudest component on most PC's. Having a bigger fan, will mean it can spin slower, and result in a lower noise level.
The 50watts of difference won't mean a hoot in the end.
The efficency is also pretty much on par with each other too
I'm surviving perfectly fine with a 550 watt by the way