Bjorn3D posted a review on the Antec 500W EarthWatts EA500 Power Supply

Since consumers have long been in the dark about power supply units, it seems common that manufacturers market their product and push features that may not actually make a difference in performance. For example, it could be seen early last year that multi-rail technology was viewed as a positive innovation. Yet later down the road we learn that a single-rail power supply unit not only offers more stable and efficient power if designed and built correctly; it would also cost less.

Antec 500W EarthWatts EA500 Power Supply Review