Assuming that we are not of the subjective "whatever power conditioner sounds best" in my system school (which is totally legitimate), I have read that there are two schools of thought on what influences sound the most with power products. One school is that incoming power is noisy so you need a power conditioner (like Torus) to clean up the power (and maybe give it a voltage boost). The downside is to make sure your conditioner has enough power to drive all your products. Another school (with John Swenson, designer of microRendu & LPS-1) says the more important factor is actually leakage currents from ground loops. This is low level high frequency noise that gets from one component to another. Proper galvanic isolation can help reduce this kind of noise but is never perfect. The solution is to make sure your power cables are of the lowest possible impedance and to have all your connected equipments connected to the same power bar so that the impedance between components' power supplies are of the lowest impedance. By keeping the impedance low, the voltage of this leakage current from ground loops would remain as low as possible so you get less noise moving from component to component. Any power conditioner that accepts multiple inputs would generally increase the impedance. Swenson's ideal solution would be to have a humongous torroid transformer like Torus as the power source and then you plug in a simpler power bar to this Torus and all your components are plugged into this same power bar to keep the impedance low. But if we can't all do that so his argument is that for high-end products like DAVE, the power supply noise filtering is already excellent so leakage currents from ground loops plays a much more important role than AC power noise.
I personally owned a 5A Torus and everything is plugged into it except my amplifier and subwoofers. After trying out Swenson's LPS-1, I had a change of heart. I removed the Torus, and got a Nordost QB8 (which is basically a ridiculously overpriced power bar) and simply plug everything including my amplifier and subwoofers into it. And in my mind, I think the sound is better through a simple power bar. Obviously, I would love to be able to install a 20-40A Torus unit so that I can plug the power bar into that unit to get the cleanest possible power. But I personally think getting everything into the same power bar and using lowest impedance power cable we can afford is the better way to go for better sound. I also think it's the reason why I don't hear much difference between USB tweaks.
Obviously, your mileage may vary. And ultimately, you should buy what sounds best to you.
