Many power supplies advertise 99% active or passive power factor correction in their supply ratings. I think that's supposed to sound impressive because it's 99% for some reason, but the little bits I can find on Wikipedia or elsewhere have more to do with what the power company sees on your lines than anything a typical consumer cares about. Plus, some manufacturers advertise an "active" power factor correction scheme as opposed to a "passive" scheme -- the word "active" usually means "better" when we're talking about PC components (see: Active Matrix LCDs, Active Noise Cancelling, etc.), but the little I've been able to find on this says there's no difference.
Is this all just marketing spin? How much/should I consider the value/type of power factor correction in a power supply?