Which PSu Should I keep

So here's the deal, I got a new GPU (geforce 275), and I bought the corsair 750w psu to replace my current which I thought was a extreme power duo 600w ( cyberpower gave me wrong documentation with pc). But it is really a Thermaltake toughpower W0117ru 750w - and I didnt know it until I went to take it out. So here's my question, from neweggs customer reviews the corsair gets better points, but is most of that due to the price? Should I return the corsair or sell the Thermaltake? I know the previous model of the thermaltake (w0116) got really great reviews... what happened that this one didn't?

Thinking outside the box here.

You might want to keep the Corsair. First, the warranty should be a bit longer for this one as opposed to the TT. (you haven't used it yet.) Second, you could now sell the TT for XXX and that will bring down the cost of the Corsair. Yes you could return the Corsair and get your money back. (possibly minus a 15% restock fee.) But you'll still have your TT that you've been using for awhile already. Just a random thought...