Corsair has an excellent reputation for high quality power supplies. They consistently earn high marks in technical reviews. They are very stable, reliable, and come with a 5 year warranty.
The Corsair VX550 power supply can easily power an overclocked system with any single video card made.
Although adequate, Coolermaster is inconsistent with their power supplies. Technical reviews have identified some issues and problems. Coolermaster offers many excellent pc cases. The same connot be said of their power supplies.