http://www.orionpsudb.com/
Basically there's three or four OEMs that make very high-quality PSUs right down to their perfect machine soldering. We're talking voltage regulation within 1%, voltage ripple within ~15mV...stuff like that.
Seasonic: Seasonic, Corsair AX Series, XFX XT* Series
Flextronics: Corsair AXi Series
Delta: Antec HCP Platinum Series
Super Flower: EVGA G2 Series