This question came up recently regarding the SeaSonic S12II 520W and the EVGA Supernova G2 550W. Another poster was saying that these two PSU's are no longer suitable for use in new builds as "the internal design is old and not for modern PCs." I thought this was odd, but I admit I really don't know the details of PSU's and have been relying on reviews for PSU recommendations.
Is this the case? If so, at what point does a PSU become obsolete?
(The reviews I've been using are from JonnyGuru, KitGuru, and HardwareInsights.)