Here are two useful sites regarding power supplies:
http://www.plugloadsolutions.com/80P...rSupplies.aspxhttp://www.johnnylucky.org/power-sup...certified.htmlEDIT: If you have trouble opening the first link, just go to www.plugloadsolutions.com and select the 80+ power supply section from the menu.
Regarding the platinum series, these two (EVGA and Delta Electronics) are likely the best options currently available under 600W, at least until the next two releases from Seasonic and EVGA are tested (though those will be 860W or higher, according to the second link above):
http://www.jonnyguru.com/modules.php...Story&reid=219http://www.jonnyguru.com/modules.php...print&reid=221And one silent fanless model from the platinum series:
http://www.jonnyguru.com/modules.php...Story&reid=244EDIT: If the links aren't working, you can find the JohnnyGuru reviews for these specific units via Google:
Delta Electronics Lazer Platinum 550W EVGA Golden King 550WThe silent option:
Seasonic Prime Fanless 500W Based on this data, even the Seasonic X series and the current EVGA lineup are probably lower tier.
By the way, EVGA already has 11 units in the 80+ platinum series (according to the first link).
I doubt these specific EVGA and Delta Electronics models will ever hit the US market, though Seasonic and EVGA might.