I have dismantled them both, Corsair is a better build, solid capacitors made in Japan, better components overall. I do recommend this PSU to anyone who want to build a QUALITY computer. It's definitely a PSU you can rely on.
Go with either Corsair or PC Power and Cooling IMHO. You can't go wrong either way. Between the two you mentioned, the HX1000W is definitely the way to go though.