I own a PS 500 for more than 4 months now. The experience I have with it has been very positive so far on source components. I do not use the PS 500 for more than 25% of its capacity.
The medium and the bass are the areas that benefit the most from the PS audio 500. The highs are also clearer and have more focus and details. I currently own the Monster HTPS 7000 and the PS audio is definitevely an improvement over the Monster.
I find the regular sinewave setting at 68 hz the best on my system with the voltage setup at 119V. It brings precision and makes my system sound more 'surround and stereophonic'. Nevertheless, I think the unit is a bit hot for what it does. It is important to use a good power cord with a high electrcity capacity transmission.