Seasonic has a reputation for high quality power supplies. Seasonic is an actual manufacturer and makes some of the high quality Corsair and PC Power & Cooling psu's. Corsair and PCP&C do not make their own psu's.
Here are some links to actual technical reviews and test results for the Seasonic S12 series of psu's:
baskinghobo - If you are positive you need a 500 watt power supply for your system, then why are you asking about 430 watt power supply?
helloworld_98 - we have no idea what baskinghobo needs simply because the pc components, configuration, and games played were not listed. It is difficult to render an opinion when the information is missing.
Message edited by JohnnyLucky on 05-17-2009 at 05:29:00 PM