Read the HardOCP review. Why would you use a unit that failed testing when you can have a unit that is electrically superior in every way? Corsair as a brand name used to mean quality in power supplies but the CX, CS and RM all use substandard capacitors. The CS and RM are also expensive. There are still very good Corsair units but they are more and more not a brand I will recommend by name just by individual unit.
As I said above do you really need 750 watts? What are you powering? I posted a link to the requirements list above.
If you do really need 750 watts you cant beat this XFX for $99. Its a rebadged Seasonic X series and one of the best units on the market. 80 Plus Gold and fully modular. The Corsair flagship AX series is also made by Seasonic and based on the X series as is the Coolermaster V series.
http://us.ncix.com/products/?usaffiliateid=1000031504&sku=78946&vpn=P1%2D750B%2DBEFX&manufacture=XFX&promoid=1064
Review. It gets Hardwaresecrets Golden ( highest ) award.
http://www.hardwaresecrets.com/article/XFX-PRO-750-W-Black-Edition-Full-Modular-Power-Supply-Review/1695/13
The actual Seasonic name brand unit is $155. This unit is identical electrically. The only units better than the X series are the Seasonic Platinum series and they are just slightly revised X series units. I have the 660XP2 Platinum for my overclocked 2600k/GTX 780 setup.