What you really want in a power filter/conditioner/distribution centre is spike protection (and hopefully improved sound), which is basically up to half a second where your spike becomes a surge, your circuit breaker should kick in after a half second. Surge protection is what can reduce the performance of your amp unless done right. All GF model do spike protection with both reviwers of GF complete front ends spending a lot of the review discussing our power products (very pro) and one was a huge 'power' skeptic who did an 'I eat crow type post' on CAM.

Also with tube gear, spike protection is basically a must, since the tube gear's power transformer is a step up which multiplies the spike.
Cheers,
Ian