The only Coolermaster PSUs that I would even think of considering are the Silent Pros. I've stayed away from crappermaster since they started using liar labels on their Extreme Power series of PSUs; any company that inflates ratings on their product so they can charge more money will not get my business. The Seasonic S2II-520 is a much better quality PSU than the GS series of PSUs from Corsair; if they are even close in price you should go for the Seasonic. I'd pay extra for the two extra years of warranty and higher quality of the Seasonic.