Here's the thing both can put pull about 800w in the hardware secrets review, but the seasonic is 650w, it has better quality components, more energy efficient(80 plus gold), it has a better warranty and it's cheaper.......
Not sure which review you were looking at, but the Fata1ity 750 output almost 1000w in the hardware secrets review to the Seasonic 800w.
It's a higher quality seasonic design vs a higher output OCZ. But that's splitting hairs. I doubt you would even notice the difference. They are both great units.