PS Audio Smoke and Mirrors?

No way man! No smoke and mirrors here! I have a P300 and have a P600 on order to power my amplifiers. There is plenty of physics to explain what is going on here. Your ears, of course, are the final measuring tool and believe me, it doesn't take golden ears to hear the improvement. Plus the protection it provides is the best out there!

Stereophile also said it made a difference to up the hertz to like 90. So it must be doing something right.

I don't know the science behind it but I do know what my ears tell me and I can hear a significant improvement in overall clarity and smoothness with the frequency set to 85-90. If I go above that the sound starts to thin out. I personally felt I got a bigger improvement from changing the frequency than I got from the box itself set at 60 (compared to no power conditioner at all)

In theory by doubling your output frequency of your AC from 60hz to 120hz will makes the power supplies in your equipment act as if they are twice as large. This is because there is less "downtime" between the full positive and negative sides of the sinewave as it travels back and forth. Imagine looking at a sine-wave on an oscilloscope as it goes between full pos. and neg. The less time spent at neutral or close to it is longer time that the power supply is being charged. If you were to provide your equipment with 180hz, your power supplies would behave as if they were 3 times larger. I hope this explanation helps.