I have owned PS Audio generators in the past. IMHO, the P300 was the best model that I owned. Not to say that PPPwasn't good device, but I had multiple problems with incoming power, and the PPP would get confused from time to time, and I could hear it clicking in the middle of the night for no reason. The new line of P3, P5, P10 are said to have less of these kind of complications.
Remember folks, one of the greatest benefits of the PS regenerators is that they produce balanced power. The other wave shaping, and variable voltages are a great idea, but I found less effect from them as compared to the balanced power.
I ended up with a BPT device that has 5 separate secondary windings with faraday shields, and have stuck with it mostly due to the weird power problems in this area. It's harder to fool a transformer than a bunch of circuitry. That being said, I would still jump on a PS300 for $400 any day!